With today's horrible university shooting, I would think this thread had a little more legs than this (no pun intended, ILikeLegs).
This type of training, regardless of the firepower used to train, prepares one for contingencies that one cannot foresee. If it's a regular un-supressed 9mm, 45, or a full milspec M4, it's about preparing your mindset to confront what may appear at first as overpowering odds. Not only this, but doing so in a purposeful, goal-oriented manner trains the mind to handle situational reasoning.
I've heard three accounts of today's events saying that in at least one classroom, the gunman had the victims line-up against the wall, and systematically shot them one-by-one. The fear of the situation, or the fear of the guns (a 9mm and a .22???) rendered the victims helpless, or so it appears.
If just one of the 10+ kids lined against the walls had some level of situational training, perhaps they would have taken a chair, a desk, or a frigging pencil and tried to bring this prick down. Then there might have been a better chance for the 20+ other victims to walk out of this situation.
I don't want to make this argument about gun-control/victim-disarmament - it's about presence of mind and preparation. It doesn't matter if you have an anti-tank launcher or a sling-shot, these types of scenarios are useful to train individuals to react in a calculated, measured fashion, which we're sorely lacking these days.