I think Cardano (ADA) which is releasing https://roadmap.cardano.org/en/goguen/ very soon will be where the miners go, to stake vs. mine that is. ETH 2.0 has issues https://news.ycombinator.com/item?id=26936244 but ADA from get go has been a stake culture. And stake means no more wasted electricity. It's like Satoshi Nakamoto back in 2008 had this great idea, then Vitalik Buterin had a +1 idea but Charles Hoskinson is fixing this whole proof of work mistake from years ago.

Algorand already has smart contracts and seems a lot more efficient and developer friendly than Cardano.

I stand corrected, Charles Hoskinson and Silvio Micali are fixing 2008 mistakes.

You can also use various PoS networks that already shipped smart contracts and aren't vaporware.

I am surprised that people still think Cardano is a vaporware. The code is there, the smart contract pioneer program just launched, people are enrolled in it. The Africa deals are there. The NFT capability and NativeToken capability is there. What is vaporware about it? There are easier ways to scam people than just building those stuffs out.

And yet we laugh on flat Earthers. Look at what I found here.

Another interesting coin is Polkadot (DOT), which, similar to Dogecoin, has no supply limit, and similar to Cardano, uses proof of stake.

> For that matter, what stops individuals exchanging private keys instead?

This could work if you were only making transactions with people you trust, at least in the short term. The main risk here is anyone with the private key could transfer the contents of the wallet. The seller could even sell the same wallet to multiple people. So you need to get the blockchain involved and transfer it to a wallet that the previous seller no longer has access to.

>For that matter, what stops individual exchanging private keys instead?

add a few more steps (to prevent your counterparty from cheating you) and you got the lightning network.