they're new and built in novel ways. we're still learning how to build them in safe ways.
smart contracts are often open source. i don't know of any other financial software like this.
its actually simple to do a software upgrade on a smart contract, the hard part is deciding when to do it.
it's a cultural thing. whoever has the upgrade keys has the keys to the castle. in cefi they're held by the bank and the government's monopoly on violence.
in real defi, the holder of those keys is a DAO..
my thesis is: the reason we don't see large cefi hacks is because those institutions have very finely tuned finality for their transactions. by slowing down transactions, and making merchants take on the risk, banks are infinitely secure so long as they can _detect_ problems in the 24+ hour window before they finalize. if a problem is stopped before it finalizes, did it really happen?
we could easily approximate this sort of slow finality into blockchains. for what i think are cultural reasons, we don't.
F
anyway, for cultural reasons i think blockchain-minded people reject slow finality because it goes against the whole "my private key my coins" zeitgeist. if your transaction can be canceled, it can be censored.