[neillyons]

The fact that they created a new chain diminishes one of the main characteristics of a blockchain. That it can't be altered.

This has always been my biggest sticking point with cryptocurrencies. It doesn't take into account that sometimes you need to fix a mistake.

Cryptos also have a usability problem. If you forget your login credentials you lose access to your account. If you forgot your credentials at a regular bank, they have multiple avenues for figuring out if you are who you say you are. Eg post etc.

[zapdrive]

Bitcoin did not break any "technicality". Technically speaking, the chain with most work is to be considered valid. What they did back then was, a bunch of miners got together and created an alternate chain with more work. So it's still technically the correct/longest chain. On the other hand, Ethereum just plain broke the sanctity by basically creating a chain that contains a transaction without a valid signature.