you practice through drills until you're sick. First you learn hitting points. When I don't have a person to practice with, I move around the Bob manikin and just attack head and torso points (because that is all he has). I adjust him to different heights and keep drilling. I'll use all my sinewali drills, imagine every kind of attack. I do not have to stop to think when someone swings at me, about what to hit. I go there automatically.
On the tuite, it is easier. I just relearn or update the way I do tuite to include the points that loosen the joints or cause more pain.
Occaisionally I need my PP fighting at work. I am not an LEO but I am a psychiatric nurse and there is always the possibility of being attacked by a patient, or needing to stop a fight, or more commonly, needing to take a patient under control who is cutting herself or punching a wall or overturning furniture in a rage. PP do help.
Your proposition question for application utility isn't really different from your own art done without attendance to PP. Don't you do drills? Did you practice punches and combinations thousands of times? Would you be able to throw a punch correctly if you had to (1) STOP (2) Think about relaxation (3) drive off the back leg (4) tighten at the end? I don't think so. It isn't really any different for PP.
You are welcome, of course, to not use them. You can swing away at places you know hurt and that will be effective anyway. Some of the places you aim for knowing they hurt, are pressure points. I could go for a pressure point almost every time now. I may not actually hit one because of movement, but I will get some. I hope I can land the one that will help me get away. A real fight is not fun and doesn't take place in a dojo world.