I know there are people that like the laser stuff. But at the risk of sugar coating it, they're not that useful.
At best, they're a crutch. For what they cost, you could take a few lessons and buy a bunch of ammo and get much more proficient at actually hitting things with your weapon. For night shooting, they're pretty much useless. They don't give you any target illumination so you're shooting blind. A good tactical light is much more effective.
If you want to shoot better and want to buy something that will assist that, get a good set of tritium-insert sights for your pistol. Preferrably adjustable, unless it's a concealed-carry weapon. Adjustables tend to be too large and have too many sharp corners that catch things when you're drawing from under a shirt or out of a pocket. You can still do tritium in a fixed though. They'll make acquiring the sights so much quicker for you- you can actually see them. Even in the daytime.