Placement counts, but . .
Clearly, good shot placement is #1, regardless of caliber, but nobody really wants to be shot, even with a .22.
A while back a friend of my wife's was walking to her car in a covered parking lot at the mall one evening when she realized she was being followed.
She had a Berretta Jetfire .22 in her jacket pocket which she pulled and turned to face him when he was about 10 yes away, aiming at his chest. He laughed at her & 'her pop-gun' until she dropped her aim to his crotch. Suddenly he had to be 'somewhere else' . . . Go figure.
The Second Amendment IS homeland defense!