You see this question asked fairly often....and a good question it is.
You'll often see someone make a snide response about the laser being a toy or crutch or some such thing and used only by people that can't figure out how to use iron sights. Of course, that same person has optics on all of his rifles....I guess that too is a crutch....if he can't hit a deer at 300 yds with iron sights, he shouldn't be out hunting.
I have Crimson Trace laser grips
on my Ruger LCR. Of all the handguns I own, it is the only equipped in such a fashion. I did it because I could and also because the crude sights on the LCR can't help but benefit from the laser.