I have mine set on auto to adjust with ambient light. I use it when I'm in my dark bedroom. It is so cool looking with the silver keys. Love it! 
Yeah it is for use in the dark but like i honestly have never needed it because i touch type and like a bright screen
I use my laptop in the bedroom with my wife sleeping. I use Nocturne so the screen brightness doesn't keep her up. In that case, there is barely any brightness illuminating the keys.
Sometimes I surf/work/read in bed at night on the MBP and the backlight allows me to do it without having a light on, which makes my wife happy. I am a good touch typist but there are still other buttons on there that the backlight helps with.
Why don't you need it again?
These threads are ridiculous.. Really, no one cares that you can touch type. Thankfully Apple thought enough of the tards who can't and appreciate the backlight, as inconceivable as that apparently might be..
Does anyone know how many individual lights there are underneath the keyboard? Or where they are..?
I just got my MBP back from Apple (wine was spilt on it - separate story), and the only problem I've noticed so far is that parts of the keyboard no longer seem to be fully illuminated.
(The lack of backlight makes me realise that yes, I did use/like it)
The backlight is actually a series of optic fibers running the width of the keyboard underneath the keys.
Wow thanks for mentioning this program. Googled it and installed it, and what a difference it made! Had a killer headache for the last few hours and this program allowed me to keep surfing. Thanks!
Just hit F5 until it turns off??But when watching a movie or something on it it's a shame it has to be turned off....oh well