For something practical, I’d look at Bitcoin. It seems to be somewhat useful for routing payments around regulation. Even at that, though, it currently isn’t ve

For something practical, I’d look at Bitcoin. It seems to be somewhat useful for routing payments around regulation. Even at that, though, it currently isn’t very good due to how inefficient the blockchain is. Maybe non-blockchain technologies like the Lightning Network will help... but if you can’t even create a successful payment network with a blockchain, I don’t see any reason to be optimistic, given that no other use cases have shown any hint of success.