I was first taught to use a non weapon mounted light. I have a general dislike of weapon mounted lights. With someone who is scared using a flashlight by pointing a loaded weapon to see what or who is there can not be a good idea. Unless very, very very well trained. Could they push the wrong button or fire in panic? Untrained and scared may limit one's ability to make good actions. Also if someone shoots at the flashlight you are holding you may lose your ability to defend yourself. I'm a seasoned citizen with an opinion. Scared people can make very poor irreversible decisions in any crisis situation. I wouldn't recommend it.
I am not exactly sure what you are arguing here. Stupid people do stupid stuff, but that's not an argument.
You do not need to point the firearm with a weapon-mounted light at something or someone for identification. Point the firearm in a safe direction (up or down) and temporarily turn on the light. The reflection off the ground or ceiling will provide enough light for identification.
Handling two items, a flashlight and a handgun, under stress is more complex than handling one, a handgun with a weapon-mounted light. Handling a flashlight and a handgun requires more coordination and good one-handed shooting skills. It is more complex, especially under stress, and requires more training and practice.
Trigger finger discipline is
always required when handling a firearm, independent from any additional equipment or stress. That's why one should
get some training and practice the use of a weapon-mounted light at the range. In a stress situation, you default to the lowest level of training you have mastered. You can't fix a training issue with equipment.
If you do not have to use the light because you can identify your target without it, then simply don't. Otherwise, you have two choices: (1) knowing your target and giving away your position, or (2) not knowing your target and not giving away your position. Shooting at someone will give away your position to some extent anyway. Night lights are a great idea to help you navigate through your home without the need to switch on the weapon-mounted light.
If someone shoots at you, you can lose your life. Blindly shooting back doesn't help your situation. Having the light on while shooting can greatly improve your hit rate.
Lastly, the choice between a flashlight or weapon-mounted light is only relevant for handguns. The
OP is about home defense, where shotguns and rifles are more prevalent. A weapon-mounted light for a home defense long gun is a MUST.