Nah. I'm not a fan of hanging a bunch of stuff on guns. Maybe it's just because I'm an old-timer, but a lot of things hanging off rails strikes me as silly. A red dot sight or something, fine. But flashlights, vertical forend grips and stuff like that just aren't me.
As far as mounting a flashlight on a gun, I have two reasons beyond just being an old fart and not going with the current trend.
1. Something goes bump in the night. You grab your gun and flick on the attached flashlight to go investigate. You move through the house sweeping the area with the light. Nothing. Nothing. Nothing. Something! Whew, it's just 8 year old Suzy. ...but because your light is attached to your gun, YOU ARE NOW POINTING YOUR GUN AT 8 YEAR OLD SUZY! Seems to me to be a very bad idea.
2. Something goes bump in the night. You grab your gun and flick on the attached flashlight to go investigate. You move through the house sweeping the area with the light. Nothing. Nothing. Nothing. Before you get to "something!", the bad guy in the corner shoots at the light. Because the light is attached to the gun, and you're behind the gun, you just died.
I'd much rather have the light move independent of the gun. Because of reason 2, I prefer the old FBI tactic of having the light away from the body.
It's more a handgun thing than for a rifle or shotgun, and not really much in favor these days, but it just makes sense to me. For long guns I'd have to take the chance that I see the bad guy before he shoots at the light and keep the light closer to the gun in the non-trigger hand. A bit more awkward, but it allows moving the beam independently of where the gun is pointing with just small wrist movements. For me at least, it's worth it to avoid the possibility of blasting 8 year old Suzy.