That is the point , very soon banks will lose a lot , because the way our economy is going is not really funny at all, our money is also losing value every day , I don’t see any point saving in the banks again , Bitcoin is actually the best now despite there is a little risk , but that risk is far bette than saving in the banks, but the most important thing is that it should be for a longer time , just as you have specified.
I will like to make some correction and this is not to look down on Bitcoin but to say the reality of people and the Nigeria Banking system. Bitcoin isn't going to replace bank and people are not running away and not because banks are better but because the government controls everything we do. An average Nigerian have a bank account but doesn't have Bitcoin, most have not even use Bitcoin before and some are even scared of holding it due to government.
Bitcoin is going to grow in Nigeria as years go but the bank will remain. They will rather work together for people to use but banks are not getting back for Bitcoin. Most of these banks are owned and operated by the wealthy people, the rest of them are own by the government and even the banks that are owned by external institutions have some shares that are been controlled by the Nigerian government, Bitcoin taking away banks is like taking away government from Nigeria.