As in the title.
Since there is no direct way to up the light range (which has been requested a lot), Luminators could be made a lot more attractive by giving them the ability to repel mobs in a certain area. (like EE2 interdiction torches used to)
Some sort of explanation could be that we assume they give off "daylight" which mobs obviously don't like and therefore avoid. Just instead of lighting them on fire it keeps/(pushes) them away.