Why would you use a seat belt in your car or helmet on a motorcycle. They are also useless if you don't plan to be in an accident. I carry a concealed weapon 24 7 for the same reason I wear a seat belt in my car and helmet on my bike. I think the concealed weapon is a much greater safety devise than either the seat belt or helmet.
Based on your logic we don't need seat belts or motorcycle helmets. I will wear a seat belt and helmet my entire life but hope to never need them. The same goes for my concealed weapon. When you think about it I spend a very small amount of my life in a seat belt or helmet. I spend a large amount of my life out in public surrounded by people. Anyone at anytime could pose a threat to my life.
If you don't own and know how to use a concealed weapon then it is a waste of time to put on your seat belt because you just plain don't care about your personal safety.