Im not a fan of bitcoin. But it cannot be in two wallets at the same time. If you deposit money in a bank it no longer is in your wallet but starts being a number on a screen. You transfer the money to the banks wallet. Then the bank can lend it to others by transferring it to their wallets.

I think the biggest obstacle for bitcoin is that it is not a legal tender and it will not be because it comes with one to many sacrifice. You lose ability to have independent monetary policy while not getting benefits of a fixed currency.