I tend to agree with
@TCHudson here, that illumination above a system can be useful. In my case, I have an Asus S712EA, and although it is a good fast laptop, the keyboard is badly designed, as it has silver-grey keys, with a mid-grey key-legends that can be in a shadow with the ceiling lights behind me, so very difficult to use in my set-up (especially the top row of Function keys, and the delete key).
If I am doing a lot of typing, I put my desk lamp on, that reaches over the top of the screen lid, and illuminates the keyboard perfectly. I made the mistake of NOT checking the F7 key on the product picture when I purchased it, as this would have indicated if it had a back-lit keyboard or not. If there is an extra icon on the F7 key, then it HAS a back-light. Many high-end laptops have this, but NOT my particular model!