Public blockchains are the backbone of Bitcoin and Ethereum - the systems that let anyone send money or run apps without a bank or company in charge. But they’re not perfect. If you’ve ever waited 20 minutes for a Bitcoin transaction to confirm, or paid $50 in fees to swap tokens on Ethereum, you’ve felt the downside. So what’s really going on? Let’s break it down - no jargon, no fluff.
What Makes a Blockchain Public?
A public blockchain is open to everyone. You don’t need permission to join. You can download the software, run a node, verify transactions, or send crypto from your phone. There’s no central company running it. No CEO deciding who gets to use it. That’s the core idea: decentralization.
Bitcoin started this in 2009. Ethereum came along in 2015 and added smart contracts - code that runs automatically when conditions are met. Today, millions of people use public blockchains every day. Bitcoin handles around 350,000 transactions daily. Ethereum does over 1.3 million. And there are over 100 million unique wallet addresses across these networks.
Advantage #1: No One Controls It
Think about your bank. They can freeze your account. They can block a payment. They can change the rules. Public blockchains don’t work like that.
Every transaction is checked by thousands of computers around the world. If one tries to cheat, the rest ignore it. That’s why you can’t just delete a transaction or reverse a payment. It’s locked in. This makes public blockchains nearly impossible to censor. Activists in countries with strict financial controls use them to move money. People in Venezuela, Nigeria, and Ukraine have relied on Bitcoin when banks shut down.
Advantage #2: Everything Is Visible
On a public blockchain, every transaction is out in the open. You can type any wallet address into a block explorer and see every coin that’s ever moved in or out. That’s transparency.
This isn’t just for show. It builds trust. If a crypto project claims it’s “backed by reserves,” you can check the wallet yourself. No need to take their word for it. This is why DeFi (decentralized finance) grew so fast - people didn’t need to trust a middleman. They trusted the code and the public record.
Advantage #3: Hard to Hack
Public blockchains are secure because they’re so big. Bitcoin’s network uses more computing power than most countries. To hack it, you’d need to control over half of that power - and even then, you couldn’t steal coins. You could only delay transactions.
That’s the beauty of distributed validation. No single point of failure. No server to crash. No database to breach. Even if one node goes down, the rest keep running. That’s why public blockchains have survived over a decade of attacks, scams, and government pressure.
Advantage #4: You Own Your Money
When you hold crypto on a public blockchain, you hold the keys. No bank. No app. No password reset. That’s freedom - but also responsibility. If you lose your private key, your coins are gone forever. There’s no customer service to call.
This is why public blockchains empower people. You don’t need a passport, ID, or credit score to use them. Anyone with a phone and internet can join. That’s why they’re used in places where traditional banking is broken or inaccessible.
Disadvantage #1: Slow and Expensive
Here’s the problem: more people using it = slower and pricier.
Bitcoin can only process about 7 transactions per second. Visa handles 1,700. Ethereum does around 30 before it gets clogged. When demand spikes - like during an NFT drop or a DeFi boom - fees spike too. In 2021, it cost over $60 to swap tokens on Ethereum. People waited hours. Some gave up.
That’s not usable for everyday payments. You can’t buy coffee with a $40 fee. That’s why Layer 2 solutions like the Lightning Network (for Bitcoin) and Optimism or Arbitrum (for Ethereum) are growing. They handle transactions off-chain and settle in batches. Total value locked in Layer 2s hit $10 billion by 2024. But they’re still add-ons - not the core system.
Disadvantage #2: Energy Waste (Used to Be a Big Deal)
Before September 2022, Ethereum used as much electricity as a small country. Mining crypto with Proof of Work meant computers racing to solve math puzzles - burning power just to add a block.
Then Ethereum switched to Proof of Stake. Instead of miners, validators lock up ETH to secure the network. Energy use dropped by 99.95%. Bitcoin still uses Proof of Work, but even that’s changing. More miners are using renewable energy. Still, the public image lingers. Critics point to Bitcoin’s annual consumption - roughly 150 terawatt-hours - as unsustainable.
Disadvantage #3: Governance Is a Mess
Who decides what changes get made? No one. That’s the idea. But in practice, it leads to fights.
In 2016, hackers stole $60 million from a project called The DAO on Ethereum. The community voted to reverse the theft with a hard fork. Half the community said no - they believed code should never be changed. That split created Ethereum Classic.
Bitcoin had the same fight in 2017 over block size. Some wanted bigger blocks to handle more transactions. Others feared centralization. The result? Bitcoin Cash. Now there are over 100 Bitcoin forks. Each one is a disagreement made real.
These splits aren’t just technical. They’re political. And they create uncertainty. If you’re a business trying to build on a public blockchain, you can’t be sure the rules won’t change overnight.
Disadvantage #4: No Privacy
Public blockchains are transparent - but that’s not always good.
If you send $10,000 to a charity, anyone can see that. If you buy a house with crypto, your wallet history is public. Your spending habits, your income, your connections - all visible.
That’s why privacy-focused coins like Monero and Zcash exist. But they’re not on the big public chains. Mainstream public blockchains like Bitcoin and Ethereum don’t hide anything. That makes them bad for medical records, payroll, or confidential contracts. Enterprises avoid them for this reason.
Who Uses Public Blockchains - And Who Doesn’t?
Traders, speculators, and developers love them. They’re the playground for innovation. New DeFi protocols, NFT marketplaces, and tokenized assets all run on public chains.
But banks? Corporations? Governments? Most avoid them for core operations. Why? Because they need speed, privacy, and control. They can’t afford to wait 10 minutes for a payment. They can’t let employees’ salaries be public. They need to fix mistakes.
That’s why companies like Walmart, Maersk, and JPMorgan use private or consortium blockchains. They get some of the benefits - like immutability and traceability - without the chaos.
The Future: Hybrid Is the Real Winner
Public blockchains won’t disappear. They’re too important. But they won’t replace banks or governments either.
The future is hybrid. Use public chains for transparency and trust - like proving a product’s origin or verifying a digital identity. Use private systems for speed and privacy - like payroll or inventory tracking.
Layer 2s are making public chains faster. Ethereum’s upgrades are making them greener. Bitcoin’s Taproot update improved privacy and efficiency. But the core trade-off remains: openness vs. performance.
If you’re a user: public blockchains give you freedom. But you pay for it in speed and cost.
If you’re a business: they’re great for public-facing trust, but not for internal operations.
There’s no perfect system. Just the right tool for the job.
Are public blockchains safe?
Yes - but not because they’re unbreakable. They’re safe because they’re huge. To attack Bitcoin or Ethereum, you’d need to control more than half the network’s computing power, which costs billions. That’s nearly impossible. But your wallet? That’s your responsibility. If you lose your private key, the blockchain won’t help you. The network is secure. You’re not.
Can public blockchains be shut down?
No. There’s no central server to take down. Even if governments ban crypto, the network keeps running on computers worldwide. Bitcoin has survived bans in China, Russia, and Nigeria. As long as a few people are online, the chain lives. That’s why it’s called censorship-resistant.
Why do transaction fees go up?
When lots of people send transactions at once, the network gets crowded. Miners or validators pick the transactions with the highest fees first. So if you want your transaction processed fast, you pay more. It’s like rush-hour traffic - the more cars, the higher the toll.
Is Ethereum still using a lot of energy?
No. Since September 2022, Ethereum switched from mining (Proof of Work) to staking (Proof of Stake). It now uses 99.95% less energy. That’s like replacing a coal plant with a solar panel. Bitcoin still uses Proof of Work, but even that’s getting greener as miners shift to renewable sources.
Can I use a public blockchain for my business?
You can - but only for specific uses. If you need public proof of ownership, like verifying a product’s origin or tracking donations, public blockchains work great. But if you need fast, private, or regulated transactions - like payroll or customer data - stick with private blockchains or traditional systems. Public chains are open, but they’re not flexible.
