It is no problem for others if some people want others to handle the security.
Then why would they want crypto currencies in the first place? They will just have no benefit of them. They will go down with the banks or banks will win and crypto currencies go down.
The benefit is that they have the possibility of holding it themselves. It's easier to have it all in one (open) system than to switch between open and proprietary systems.
The proprietary ones can censor people.
