Lasers are perhaps most useful on guns that do not have usable sights--S&W J-frames, for instance. But they also are useful on guns that you anticipate shooting from unorthodox shooting positions, or shooting weak-handed, or shooting at very close (arms length) ranges where you may be entangled and the gun cannot be brought to eye level.
They have a use, but that use is specialized and may not be for everyone. For myself, my serious guns have lasers on them because the technology exists, it works, I know how and when to use it, and I want every advantage I can get.
On the weapon mounted light question, I want a WML and all the lumens I can get with a lens that provides a good amount of "spill" for use indoors. If you want to use the light without pointing the gun at an unknown object, a powerful WML can bounce light off the floor with the gun at low-ready, or can bounce light off the ceiling with the muzzle pointed straight up. This indirect lighting can be useful for illuminating whole rooms and can substitute for a handheld light in circumstances where you may want to have one hand free.
Last edited by Oregon45; 12/14/18.
