That's only the words of extremist of bitcoins fans and field IMO, I think it's still too early for bitcoin to actually replace fiat or change the financial system. Bitcoin can be a great currency on the online field and for conducting transactions throughout the world.
The argument is that bitcoin would make the bank to disappear literally, because it is a revolution in the way we are going to be seeing and using money going forward. Those banks that chooses to hold on to their "stone age master-piece," well they will be left behind and those innovative ones will be the banks of the future, as simple as that, life is dynamic!