Banks is a more elaborate system, at this point. You can't make installments, loans, and more. So bitcoin won't be able to replace banks for a long time to come.
Sometimes people exaggerates concerning bitcoin and its relevance in future, bitcoin is a technology, and the technology is not up to thirty years in existence, so let us keep the comparison of bitcoin domination and banking system of fiat currency apart, because having the mindset that bitcoin will replace banking system in future time is an exaggeration of personal, before existence of bitcoin bank is in the existence and fiat currency is already on the ground.
So I will not advice people to concur in such speculation of bitcoin taking banking system, from my perspective, bitcoin can come to end any time and any minute because it's currency it's not generally accepted across the nation's, so base on such principle I don't think we should consider bitcoin that much as a currency that will dominate fiat or banking system in future time.