(A) Old habits die hard, and (B)it is far better to have a firearm and not need it, than to need one and not have it. You might as well ask me why I carry a fire extinguisher and first aid kit in my vehicle. The odds say that you'll never need the firearm, the fire extinguisher, or the first aid kit, but if you do you'd better have them on hand and know how to use them. Prepare for the worst and hope for the best.