And this is an issue I've been preaching about for decades! I've yet to have a student who says they practice with their weapon actually practice in a useful way. Their idea of practice is to go to a gun range, observe all range safety requirements, don ear and eye protection, and shoot at a non-moving or non-maneuvering target using their strong hand. All of these are ideal conditions for target shooting, but usually worthless for a real-world defensive situation.
First, you won't be wearing ear protection, which means the moment someone fires you're going to lose your hearing and depending on your physiology you may also partly lose your balance. You're instinctively going to be using your strong hand to push, shove, punch, or otherwise engage with an attacker, not reaching for a gun. This I emphasize to my students by throwing a ball at one of them unexpectedly. Every one of them reaches with their strong hand to grab the ball, they don't reach for their weapon. Instinct drives behavior far more than training, so if you're not shooting with your weak hand, you're not proficient. And God help you if you're carrying a 1911A1 or similar pistol that doesn't have an ambidextrous safety.
Lastly, there's rarely an opportunity to get into a Weaver stance to shoot. More likely you're going to be on the ground, off balance, against a wall, arms pinned, or otherwise encumbered, so how much do you practice shooting with your gun at your waist and doing instinctive firing vice aimed fire? Probably not very often.
Most people are proficient shooters on a range, but are totally unprepared for defensive situations.
