Good question,
Maybe for exporting out to LW? I think they export cameras, lighting and mesh layers, but have not tried yet to see exactly what it does do. So a Very good question my brother, I don't have a clue either lol.
I have not gotten any light source to work right yet other then the sun or add a new sun, no lighting has worked for me yet, but have not really had the time to explore that further yet, been playing in other areas.
DT