Light is good, light is your friend, BUT I don't think a light should be on a weapon. And for the reason often stated, pointing the light also means pointing the gun.
Now, as others have said, you don't have to point the light directly at the object (potential target), but unless you are a highly trained individual (and how many of us really are?) who
never breaks training, then at some point, you
WILL point the light (& gun) at someone.
Now, while this may not be bad tactics (depending on the situation) it certainly is bad manners.
The fact is that if you are awakened in the night, you don't know what is going on. The bad guy does. The only thing he doesn't know is if you are armed, unless you are one of the "rack the pump gun" types, or you announce you are armed.
I see no point to a light on a carry gun. Or more correctly, no point for me...
Added weight and bulk (even if not much) and questionable utility. Add in the fact that most holsters aren't made to fit a gun with a light...
I do find it somewhat humorous that some will explain how a full size gun is "too big" for CCW, and then they go on to choose a smaller gun, and add a light, which brings the total package back up to (or even possibly beyond) the size of that "too big" gun that they spurned...
You should do what makes the best sense to you, considering your personal situation. My situation is that I am not a cop, nor young and fit. I live in the country, in a small house, with one other person (and some pets). Outside of a (rare) power outage, there are some lights on in my house, 24/7. I have a yard light, and other than my car (a short distance from the front door, and not in complete dark, either) there are no things of significant value (or portability) outside my house. So, for me, the point of having a light attached to my defensive firearms is rather moot.
As to having a light when out and about, I'm still in the camp of "the light should not be on the gun". In my life, there is nothing that requires me to be out in dark places, and so, I rarely do it. Also, there is the consideration that a light, while useful, is not desperately needed, as absent night vision devices, the bad guy can't see in the dark any better than you can.
I'm not going to be clearing any dark buildings, nor do I have family members that might come and go in the middle of the night. My wife's 35lb shaggy mobile alarm system serves quite well, and is fairly cheap to operate (unless the price of treats goes up
).
your situation could be completely different, and you should evaluate things based on that, not on what any well meaning internet advice says. Take it under consideration, sure, but don't blindly follow it just because the author sounds like they know what they are talking about.