I build race tracks, full sim builds, and lighting them can be a problem because of the maximum 20 meter radius: in real life, lights are usually outside the track and shining in, so the lighting ends up looking wrong by having to put invisible light sources close to the track. With the ability to use light sources from longer distances, we'd be able to make much more realistic looking tracks, with more realistic reflections and shadows on the cars. I can also see this being a big benefit to clubs, other sports venues, airports, and live music setups. There have been so many changes to lighting and shaders in SL, but the light radius is still what it was when I started in 2006.