Banks are hacked very regularly, probably a lot more than you'd think. It's just much more difficult to actually extract money from them. With Bitcoin, all you

Banks are hacked very regularly, probably a lot more than you'd think. It's just much more difficult to actually extract money from them. With Bitcoin, all you need to do is copy 32 bytes (the length of the ECDSA private key) over and over and suddenly you're a millionaire. It was a little more complicated in this scenario, since the attacker exploited an application flaw and appears not to have gained access to any private keys, but they still gained permanent control of the coins in a simple manner.