The USPSA and other like competitions are good to go through, especially to grow self-defense skills. 90% of people that buy a gun for self-defense have no clue and believe just taking the firearms safety class is good enough, much less hunters ed. USPSA probably saves more lives in defensive encounters than it takes from accidents, though I'm not saying USPSA is in anyway unsafe. The competitions teach a lot of things that people don't practice or realize they need like:
1. Speed and sense of urgency
2. Using cover
3. Recoil control
4. Gun safety when moving and operating it
5. Malfunction clearing
6. Thinking and operating under stress
7. Doing multiple things at the same time
8. Awkward shooting positions
It's a good learning experience and people know what they need to improve on. It's important that people know it's still a game and gaming the system. Like knowing you usually reload behind cover and not on the move. Or shooting off balance leaning out from cover. Or identifying a threat and being aware of innocents around.
Safety - The competitions are very safe for what it is. The courses of fire are set by USPSA and extensively checked for safety. The rules are strict and classes are required before shooting a match. New shooters (and old) make mistakes and it is better they make those mistakes on the range than in a defensive shooting.
For unsafe guns, they're supposed to be drop tested and still follow specs. The enforcement mechanism on that is a ND will result in disqualification and being sent home and no competitor wants to do that. Using reloads doesn't make a difference whether it's USPSA or shooting bullseye pistol.
For a more realistic experience, IDPA stays truer to the self-defense philosophy with more realistic scenarios, rules, and production pistol and equipment requirements.