I guess we might as well not bother with passwords either or disk encryption either. After all other exploits exist and there's not point protecting against any

I guess we might as well not bother with passwords either or disk encryption either. After all other exploits exist and there's not point protecting against any attack vector unless all are covered. Security comes from many layers, and is a constant and incremental process. "Someone might get in by breaking a window" is not a reason not to install locks on your doors.