I agree. Bitcoin can not destroy the banks. He can only infiltrate the banking system as an alternative currency.
So what exactly is your point? Somebody can do this in bitcoins as well. You can get a loan and follow the same procedure with bank loans. In bank loans, you need a collateral or a good business plan. Along with these, you also have to submit your whereabouts. There can also be a trusted company that offers bitcoin loan to people. Insurance, car loans, housing loans, all of them can be in bitcoin form.
Bitcoin is much more than a currency. Bitcoin can perform all of the things a bank can (or perform even better to some extent). Online banking? Bitcoin got that.