What interests me is that it makes sense to start a “bank” that will take care of customers like traditional banks do. Opening an account, buying a crypt, maintaining a computer, etc.?
What you are describing is what is available today through crypto exchanges, which do not differ too much from traditional banks. Some of these companies even offer interest on deposits, and it should be mentioned that some of these companies have been in this business for many years, and that they have experience with secure storage. I'm not sure how safe traditional banks would be in that sense, because if someone hacked such a crypto bank and stole say 100 million in BTC - it's not the same as if someone stole $100 million from the same bank.
With all of that, it would be for many the complete opposite of what Bitcoin should offer everyone, and that is for everyone to be their own bank. I am personally against such an idea and I would never use something like that.