I have Crimson Trace Laserguards on three of my carry pistols. I rarely utilize them at the range. If I'm just punching holes in paper, I find the iron sights much more accurate. There are benefits to the laser, though. Primary among them, I've found, is to help with developing stability and stillness when I shoot at longer distances. Watching how much that dot actually moved at 25 yards was an eye-opener. They are also really fun for teaching new shooters. Same reason as before, primarily.
What's the big advantage? Being able to put rounds on target if I can't get a good sight picture. If I have to hide under something or behind something, or can't get the pistol up to eye level, I can put the dot on the target and know I'm going to hit.
It definitely increases the range at which I feel comfortable with my tiny little CW380, though. 20 yard killzone shots with that are no problems whatsoever.