Lot of mountain lion where I hunt. Even when rifle hunting with a large pack and rifle on a sling,I carry a 10mm Glock across my chest in a holster attached to an oversized belt. No way to unsling the rifle if I'm knocked down. But I might at least have a chance to get off a shot if I am face down, maybe even with it still in the holster. What are the odds that scenario occurs? Not much. But it feels better to have a defense just in case.
I lived in LA County when the Rodney King riots broke out and the riot paths were getting close enough in my city that law enforcement was patrolling in caravans. I got some comfort knowing I could at least fight if necessary. I've had a handgun safely contained next to my bed for 50 years but never had occasion use it in self defense against an intruder. In terms of probability, a critic could say an accidental discharge may have been a greater probabiliy since self defense situations never happened.
But neither self defense needs or accidental discharge ever occurred. So probability means nothing to me. Having a means of self defense means a lot and makes me feel a bit safer.