Comment by darkmighty

The difference is that conventional banks can roll back transactions. The normal banking system is essentially a consensus mechanism "A: I owe you this amount. A: I just transferred you this amount, ok? B: Yup, accepted, thanks." If something goes wrong, A can say "A: Woops, I made a mistake. Reverse please, here are the laws stating in this case I have the right. B: Alright, I must comply.". In cryptocurrencies, by design, "the code is law". And this law does not predict reversing transactions. So you can lose any amount of currency due to an illegal act or even some simple error, like transferring to a dead address.