don't strain your brain too hard thinking about any other experience besides your own.
What if you work in a busy environment and leave your phone on a desk, then leave the room for a while, and while you were gone you missed a message and the ensuing vibrations? You make it sound as if the screen is always on...it's not. Some people don't have time to pick up their phone every time they come back from leaving the room.
Some people work in different environments. They might work with chemicals or in food preparation, requiring gloves. Maybe they put their phone on a shelf and can't reach out to touch it every few minutes.
A light would help these and many other people. Just because you don't require one doesn't mean others don't.
Why are all you anti-light people so adamant? If apple did add a light, it would make a lot of people happy. They would no doubt do it in a subtle if not invisible-when-off way. And they would let you turn if off completely, so why are all you knuckleheads wasting your bandwidth arguing against it? All you're doing is making yourselves look like lemmings. Take it from a fanboy...you are giving fanboys a bad name.