I can think of one circumstance when I might want a light for my Kindle - when sharing a hotel room with someone who wants to go to sleep when I want to read in bed before sleeping.

My Kindle came in a Pategonia case which is lightweight and sturdy but lacking fancy features. The Kindle has to be taken out of it to be used. So far that suits me fine but if I really used it a lot I think I'd want a cover that could stay on while I read.