I have been shooting some kind of gun since kindergarten. I have shot many tens of thousands of rounds through everything from .22 LR to .44 mag. I qualified expert with both the M16 and the .38 revolver in the Air Force. I have lightened the pockets of many of my shooting buddies shooting steel targets with both pistol and rifle. Simply put, I can hit what I aim at.
I have a Laserlyte training cartridge that I practice with on a very regular basis. I use small reflective tape targets that are randomly placed in my garage at ranges from ten yards and less. They light up like a flash bulb when the laser hits them for instant feedback. This helps me reinforce that my aim is true, my grip is good, and that my trigger work doesn't interfere with the aim or grip,
Coincidentally, I just installed a Crimson Trace Laser Grip on my G19. I saw it on Ebay and the 5 star vendor had a very nice price on it so I pushed the buy now button. It arrived on time with new batteries and it works perfectly.
Does it improve my shooting? I sincerely doubt it. Are there situations where it could give me an advantage? Certainly.
Since I already have a set of Glock tritium night sights on the gun I don't have to depend on a laser to take aim in the dark. The Laser Grip works with my IWB holster and doesn't take up much room on the G19. It weighs maybe an ounce with batteries.
I believe that dry fire training with a laser cartridge is beneficial to me. I think that while I feel the Laser Grip is a bit of a novelty, there are places where it could be mighty handy. YMMV!