I am very sure that one day, traditional Bank will begin to accept Bitcoin as a legit medium of exchange, people need to be given freedom to deposit their BTC directly just like the regular money.
Why would you even want to do that, to keep your bitcoin in the bank?
With bitcoin, you are supposed to be your own bank and not to put your own bitcoin into someone else's hands, basically loosing control over it. Having said that, I have no doubts that many would still do that, no matter how stupid and shortsighted it actually is as people nowadays are doing even worse thing, like keeping their bitcoin on the exchanges.
Well I guess the point is that most other places are dangerous and they would feel more comfortable if the bank is in responsibility for the safety of it. You have to remember, if you give your bitcoins to anyone, exchanges, wallets, whatever, then it's at risk and you can lose them at any given moment, those places may just say "we got hacked" and steal all your money or they could even actually be hacked for example.
If you personally hold them, it's your responsibility and if you someone get it stolen then it's all on you and you have nothing to do. Whereas, if you put it in a bank, they can't just say it's hacked, they have to pay you, so you have a guarantee that your money will be there, and you will not be worried about it.