How to use the 'Maximum Distance' parameter on lights.

I’ve been messing around with the ‘Maximum Distance’ parameter to try to deal with those annoying ‘lighting pileup’ issues on my maps, but it doesn’t seem to do anything at all. Does anyone know what this is for? Is there a proper way to use it? The Source wiki just repeats the FGD description “This is the distance that light is allowed to cast, in inches.”, which is less than informative.