^
All kinds of this. USPSA competition definitely isn't about tactics, but people who get into it with even a small amount of drive to improve unquestionably come out the other side able to shoot faster, safer, more accurately, and with lower mental "task load" than before they started competing, and not by a small amount. I've watched lots of new competitors go from slow and somewhat scary to a level I'd call safe and competent just over the course of one summer.
Obviously specific improvement levels vary from person to person, but the only people I can think of who haven't improved at all are the ones who get offended and quit when they DQ for doing something unsafe and those who simply keep going doing the wrong thing despite receiving tons of good advice.