Ho I do not disagree but coming from Canada where we have been talking about open banking for the past 10 years without any progress I will take a smart contract any day over the big 5 banks that we have today.
The question is not if it can be done outside of the platform, it is how much time it takes. I would encourage you to try to code a smart contract even if you dont like the concept, it is eye opening.
The fact that would have a standardized VM for money where you can write small programs to implement your law is just another level frlm what we have.