I don't think it will ever replace the bank. Blockchain has been here for a few years now and there has been similar talks about blockchain replacing banks but today, it is hard to imagine that blockchain will replace banks as it is very risky as it is vulnerable to attacks and there will always be some issues on the codes that hackers are willing to explore.
Talking about technical aspect, banks especially their e-banking also have a hole that can be exploited by hackers but their centralized natures could overcome it. While in decentralized system like blockchain reversible transaction is just impossible. Maybe we need to resolve this first.
Reversing transaction might be exploited by some users just like how people used paypal for any transaction. While banking system is different from crypto system one must use each other and not to just replace it because it might help to solve the long process issue of the banking system.