It's funny that you mention that. I know 2 people that carry but routinely don't wear seatbelts. One says that it's uncomfortable and the other says that he doesn't mainly b/c he is required by state law to wear it and that ticks him off. I asked him if he would stop carrying if he was required by law to be armed all the time and he said no. I don't get it.
I've never seen personally or known anyone who has used a firearm to save themselves. But I have witnessed many automobile accidents, known people who have died in them, and been in one myself. A seatbelt is many times more likely to save your life than a gun is.
Exercising, watching what you eat, and not talking on the cell phone when driving is also many times more likely to save or extend your life. But how many carriers do those things?