I don’t like lights on my pistols. I don’t like lasers on my pistols, both reasons go back to I would rather not give away my position.
From my experience in LE, you won’t give up your position if you know how to use the light. In an HD or even CCW situation, you’re in a different world than the military and much more like LE. The weapon light is used in tandem with a handheld. It also guarantees the ability to see your target if you can’t find your handled for whatever reason.
If in a building, illuminate the room by shining the handheld to the ceiling. This will get you complete illumination if using at least 300 lumens in a room. This keeps you from being tunnel visioned. Once you see the bad guy, you can challenge them and even coerce at gunpoint. This allows you to turn the gun light on and use your other hand to call for help. Or, worse yet, it lets you drop the handheld to shoot two handed.
If outside in public, again it keeps you from being completely in the dark if you need your other hand for something else.
Its always a good thing to see what you’re shooting at.