I understand your concern about the potential risk associated with banks, but this can make some people's bitcoin lives easier. At least, this is what they think.
That's just the way it is. If someone like my aunt is going to end up buying Bitcoin at some point, she's going to do it through her bank and deposit it there, just like a lot of people on the street. Even billionaires who buy large amounts usually do it through centralized entities and deposit it there. Today I have seen the case of Mark Cuban, but Saylor at least initially said that he did it this way, but he did not shy away from the idea of self-custody in the future, which I do not know if he has already done, but in these cases I imagine that they want everything transparent as they are under scrutiny and also the possibility of suing a company if something happens with what they have there.
Another thing is that I personally plan to avoid banks like the plague for Bitcoin purchase and custody.