This is the same thing as using a rifle scope as binoculars to hunt with instead of binoculars. People do this all the time, but it breaks the firearms rules and is a wonderful way to get yourself shot if you do it to the wrong person, or shoot something you don't want to.
I was listening to a podcast a while ago with Massad talking about revolvers and double action only trigger jobs. He basically argues that defensive revolvers need to be converted to DAO both by removing the hammer spur and the single action notch so that it could not physically be cocked. He had several examples of accidental shootings because of 1) improper training (the cop was told to cock the hammer for a 'critical' shot - the cop interpreted that as 'important' not 'precision/long range') 2) accidental (the revolver got cocked by catching on clothing before the draw) 3) habitual (in the heat of the moment, the cop cocked the hammer because that how he practiced some times). Then, with adrenaline running through you and loss of fine motor skills, and having to do things while holding the gun, it becomes too easy to discharge the gun. We have sympathetic reflexes between fingers and between our hands (grab a flashlight with one hand and the other one might squeeze as well). We might get nudged or be shaking so badly our fingers can't stay steady.
What I came away with from that podcast is that while we should strive to meet the four rules, when the hammer falls (pun intended) we react and our training may not be enough. So, knowing what might happen during an actual fight, what can we do to maximize our success and minimize any potential negative consequences? This convinced me that my carry revolver will be DAO and have a reasonable but very smooth trigger (not super light).
Crimson trace lasers have always intrigued me in that their switch is activated be the middle finger. But, in the heat of the moment if you were holding a person at gun point (and that very well may happen in a defensive use of a hand gun) and needed to activate the laser, you could wind up pulling the trigger. (I know, keep finger off trigger - that advice won't console the family of the dead person). I think that for CT lasers, if I had one, I would never train to activate/deactivate the laser. If you have a grip on the gun the laser should just be on - and that needs to be taken into consideration when selecting CT grips. Do you want a laser activated every time the gun is in your hand? For a carry weapon, maybe, for a home defense weapon, no. So, maybe, as cool as CT grips are, we shouldn't really be putting them on home defense guns. Just a thought.
It's the same thing with weapon mounted lights. When used correctly, you should never have to point the firearm at someone to illuminate them - there's enough spread in most of them that you should be able to identify someone by holding the gun in low ready position. But, in the heat of the moment, where the fight might last 2-3 seconds top, are you so sure of yourself that you aren't going to point the gun at the person to identify him? After thinking about it for 2 seconds and being honest with myself, my answer is that although I would love to say I wouldn't point the pistol at them, I can't be certain. The reason is that I've been using flashlights (handheld) since I was tiny and I've learned to point the beam of light at whatever I'm looking at. How do you condition that out of someone to the point of 100% confidence?
Remember, when the stakes are high, K.I.S.S.