Originally Posted by fnfalman
Because my .300 Winchester Magnum rifle fires too weak of a cartridge and I'd need a 10mm to protect myself against creatures of all kinds?
In South Texas, at least, the pistol is handy because most encounters with illegals and the cartel "coyotes" that run them take place with very little notice and at very close distances, where a full-sized, bolt-action rifle is of little use. The illegals and "coyotes" normally hide in brush or take cover when they fear someone might be around, and when you encounter them it's normally by surprise and at close distance.
A handgun is very much a plus in situations like that.