We all know how the banks system works, soo you wanna to get interest at your coins, this is already offer at bitcoin with its high volatility, do you really wanna put your coins at bank to they lend your coins to others?
Believe or not but this is already happening.
On several exchanges you can lend out yout Bitcoin for some small daily interest rates.
I myself would never do this but I know a few guys who think this is a good way to make some profits and are doing it.