Bitcoin could not be integrated to centralized currency system so it should be treated differently. In this case if banks will join bitcoin then the coin will be coming from the the people and not for them. However, they can process from fiat to coin exchange to where this is another form of earning from them from the process they will going to make.

Sounds like another job for the bank clerk and it will surely involve high value of exchanges. Another money making activity very simple, fast and easy.