We still need the bank to convert bitcoin to fiat. There are still merchandize we cannot buy thru bitcoin, so we need to convert. Without the bank, this cannot happen.
Yeah but when bitcoin becomes a main currency which you can use everywhere you have to imagine it like that.
Still I think they wouldn't let that happen banks have way too much money to let it get to the point where that money has no value. I don't think anything can beat banks by this points cause the world is run by them.