Bitcoin does not need middleman or 'banks' in having their transactions. This is the reason why bitcoin impose a big threat to governments specifically the banks. If all people turn out to be using bitcoin, then it will be a disaster for them, they will be useless if this event will happen. But of course, not all the people can afford or has the ability to join because of personal excuses so that banks are still in function. Its just the function of banks will be lesser than what they are in the past.