I’ve never shot anyone, and hope never have to, but the .45 by my bed is helpful for sleep.
I've never shot anyone either and I also hope I never have to.
The two incidents in which I was threatened with serious harm were both resolved non-violently just by the display of my gun without any shots being fired. I think the vast majority of those 2 million cases each year of a gun being used to deter a crime are probably resolved the same way. Just showing the bad guy(s) that you're armed often ends the threat.