Just shot a lights and lasers match. Illumination only when actually engaging the targets, otherwise darkness. 120rds pistol @ 10m. in various matches. Hand held light; weapon mounted light; weapon mounted light and laser. 40rds rifle @ 100, 75, 50 and 25m. Prone, sitting, kneeling, standing. 160 rounds total. Shot 150 5s, 10 4s. 790x800, 96 Vs. Same targets as used in daylight. Groups and scores not much different than in daylight.
A laser is a very effective aiming device. It is also a very effective training device. A weapon mounted light is also very effective.