I agree with your assessment. Without a lot of training, pistol lasers just aren’t worth it.
If the laser is mounted at 6 o'clock to the barrel and you can see the laser dot above your sights at some distance, you have a converging zero at whatever distance your laser dot, sights, and bullet impact meet. As you increase that distance the laser dot will rise higher above your front sight. As you decrease that distance, the laser dot will fall under your barrel.
For parallel, imagine a second laser replacing your sighting system. From your muzzle to infinity, the distance between those two beams will never change.