The early banks understand that we are in a different financial age, the better for them. The earlier they accept the fact Bitcoin has come to stay and adapt it as a means of payment, the better for all.
The convenience of using Bitcoin should encourage them in the first place, then they can look for ways to regulate it if they want to.
Bitcoin is growing rapidly, consumers will leave it if banks don't adopt bitcoin soon and this is what makes me believe that slowly bitcoin will become a global currency and will become the most profitable asset.