In an actual self-defense scenario, there's no timer going "BEEP!" to let you know it's time to throw down and start blasting. Whatever cues there are are likely to be visual, not audible, and on top of it they might be murky or ambiguous and occurring in a rapidly evolving situation. It's not going to be an El Presidente drill with someone there to give you your score at the end.
(Which is not to say that technical gun-handling skills aren't important. They are! But they're just one piece of a complicated puzzle.)
