1) A competitive situation is important when training for the real thing. You're under pressure to hit the target in an area that scores points, you're under a time crunch, depending on the stage you may be using barricades, obstacles, moving targets and other challenges, and you have a bunch of people watching how you do. All that, and you have to be careful of safety rules such as being aware of muzzle direction, safely drawing from holster, and above all not dropping your firearm.
Anyone can practice on a target range and meet high standards with enough practice, but that can change when you have to move, fire at moving targets, perform reloads, fire from behind cover, shoot through small openings, and do it all as fast as possible while following safety rules.
2) The problem I saw with MPPL competitions was the lack of trigger time. Most of the time was spent watching everyone else shoot and helping reset or tape targets. Maybe 15-20 minutes of shooting out of several hours standing in the midday sunshine trying to stay hydrated.
if they could have split us up into smaller groups among more stages running simultaneously, I would have continued going.
1) That's mostly why I started shooting USPSA. Well, mostly to "do more" than shooting on the bullseye range, specifically shooting and moving. The pressure of the (fcuking) buzzer does simulate stress. Ya, not stress of "real thing", but point (at least my take away) is your performance (mind, body, whatever) is affected by stress, adrenaline, etc. It's not necessarily a bad thing, but key to realize that it happens and some level of exposure of if/when it happens. Also the "problem solving" aspects, which (at least to me) include assessing of target difficulty, and yeah the fumble and occasional malfunction. And YES, the stress of competing with your friends definitely matters, which makes it fun, challenging, and sometimes embarrasing.
2) Yeah, that is one sucky part of it. You're there for 5+ hours for maybe 2 mins tops of shooting. The range does make a lot of limitations for groups waiting on neighboring stage. I've been to some mainland matches where every stage is a separate bay. However, in some cases, that leads to folks taking a ton of time to walk through the stages. . .