If all holders gives them details then it will be it safe or not?
Safe in what aspect? the banks always do collect the information of their clients whether you are a depositor, a borrower, they'll get the necessary details of their customers. Having our own wallets make us the bank itself. Although, I've heard that there's already some bitcoin banks but the duly purpose of it isn't being the bank itself but probably into business like lending bitcoin to their users or something like that. I'm still confused how they'll work.