Just as there is no substitute for really being hit, in order to learn how to take really being hit, in the unarmed combatives area, there is no substitute for really experiencing incoming ordnance. Modern multimedia training methods, and visualization, can only go so far. This is my opinion.
Being able to survive one’s first shooting situation may well depend upon having reached a state of unconscious competence with one’s weapon, so that operating the weapon is reflexive, and therefore inoculated against stress.
Unconscious competence, I believe, has a much longer shelf life than “perishable skill.”