I have been in combat. When we were training before deployment we used an electronic vest that said if we were “hit” and then had a card that told us what our injuries were.
This training was a joke!
Paintball training does not carry the weight/reaction of a true weapon and the confusion factor of combat is missing. But it is excellent training. Getting hit with a paintball is an excellent way to learn that tactic you thought was so cool, will NOT work. It is perfect for team training, tactics, learning team communications.
The US Army is going to this training because it is much more realistic without getting a squad killed by “friendly fire”. As long as you appreciate its limitations, and understand that your first introduction to real incoming fire will be heartstopping no matter how much you have trained, it is valuable!
Like everything else you get used to it. I can now sleep through incoming rocket rounds. If you hear it didn’t have your name on it.