Protecting the bank during a robbery is a red herring argument. As a CCW holder it's not my job to try to break up a robbery or protect the bank's money. I'd only draw if I felt I had to to protect life, that would be a judgment call. Most bank robbers don't bother the customers, they just want cash and run.
I'm more concerned with being able to protect myself and my cash deposits or withdrawals to and from the bank. I don't want the inconvenience of having to disarm in the car (leaving the weapon more vulnerable to car robbery) then have to re-arm after my transaction.
Of course, the drive-thru is always an option...
The right to buy weapons is the right to be free. - A.E. van Vogt, The Weapon Shops of Isher