I am not aware of anyone using a lazer sight or flashlight on a gun that ended the fight. At the range or out plinking.. they are both useless. for the house.. just embarassing.
You're talking to one. Normally I'd agree with you, but in the PSD field, a new use for pistol mounted lasers, usually the internally mounted ones, surfaced. Most of the windows in our vehicles will only go down 2 or 3 inches due to the armor configuration, especially in the BMW's we used to use. When you have a threat at close range, the easiest way to deal with it we all found was to crack the window down as far as it would go, lase the target, and engage it. Understand that most if not all vehicles whether they were level 7 or level 1 armor do NOT have firing ports built in to their designs.
As for the weapon mounted lights, on a pistol, ya I agree I'd rather have my light source in my hand, since when entering an enclosed are, mainly rooms/etc, the easiest way to light it is to hit the roof with your light. The reflected light lights up the entire space usually, not just the direction you would normally point your light. Take that as your free tip of the day. This way you can have your weapon covering your Arc instead of pointing at the roof, haha.
Also, Re the Glock weak rails, this is what I was referring to earlier as to the net and weak Glock rails. It isn't just those years either, it is still a problem, although much less so. The bottom line IMO is that plastic pistols aren't designed to shoot 100,000 rounds over a year, and they shouldn't be expected to.