The best use for lasers, for me, is when it comes to refining someone's shooting mechanics.
It's relatively easy to track the laser dot as the trigger is being pulled. This way, you can see if the shooter is jerking the trigger one way or the other, or if he's anticipating recoil, resulting in low shots.
Back when I had a S&W 686 equipped with a laser, I'd load up some "bunny fart" .38 Special wadcutters for those firing their first centerfire handgun (after initially training them with a .22 Ruger 22/45 pistol). Usually, the first shot would have good accuracy, and then the subsequent shots would be low.
Some would deny flinching, but after I turned on the laser, and took a quick video, that quickly dispelled nay doubts.