Why would anyone keep bitcoins in a bank? The whole concept of bitcoin revolves around using peer-to-peer technology to operate with no central authority or banks. It eliminates the nasty charges and unnecessary money sucking procedures that banks carry out in the name of providing you a storage for your money. You're giving banks power and underestimating bitcoins if you're keeping them with banks. Disgrace!
One word - Interest.
Right now, there are no avenues for me to safely invest my bitcoins. If a bank started accepting bitcoin deposits and pays interest on them, I would be ready to give them a chance.