This is extremely curious... What do you think banks' "own purposes" are?The money has been used to prop up failed too big to jail bankers and banks, which can take the money in form of higher salary, bonuses and pensions. The banks themselves have had access to cheap money for loaning, but the appetite for risk is not there so the banks just uses the money for their own purposes.
I'm probably the wrong person to ask about this big economic experiment though.