Well, those who invested or dealing in cryptocurrency only will need banks soon. When BTC hits ATH, they will convert it now into fiat and where do you think they will put that huge money? definitely in banks. Banks always serve as a great part, especially in our economy. It has a lot of advantages and makes it very important that must exist in a community.
Some will do that, but whales which are the biggest holders of bitcoin are getting bigger instead of smaller this means they are not showing any interest in selling their coins and keep that money in the banks, they are showing they trust in bitcoin and that they are still accumulating it despite the fact bitcoin has been unable to break its previous ATH for 2 years and a half, so when bitcoin reaches a new ATH I will not be surprised if people sell their coins to get a stable coin and wait for the crash just to get more bitcoin in return.