How does a lighted front sight help identify the target at night? Either by red flood light, or night vision amplification, the target needs to be identified. Most of those will put enough light on the target to get the front sight on it, or have a built in sight themselves.
On a handgun they might help, it's a close range weapon. Many of those owners state the real benefit is they can see where the gun is located to grasp it. Once in the hand, some method is necessary to identify the target to even know if it's a threat.
With a rifle, the target is likely much further away, it's not nearly as much a definitive threat, and identification even more necessary. If it's hunting, are you targeting a sounder of pigs, or an out of season herd of does and fawns? Or, feeder calves?
You need to illuminate your target to identify it in the dark, and that usually settles the issue of what sighting method you use.
With military weapons, the red dot is used, and the specification states it can't be emitted forward to detect it. Goes to the tritium sight, in tactical use it could give away where you are as you pass hidden intruders.
Gets complicated at night, which is why the Armed Forces trains in it so much to get things ironed out before going into combat. There's a lot to it.
