Thoughts:
1. If they added an additional light to the back, they're wasting battery life.
2. If they altered the internal rear-reflective divider so main back-light provides the light for the logo, then they're reducing the screen's brightness from the front. (Meaning if the user wants to use the phone at regular brightness levels, they'll have to crank up the back-light.... and again drain the battery.)
... now if it were naively done as an alternative notification option (instead of vibrate, or activiating the entire LCD for on-screen sleep notifications) then it could
save battery life and actually be worth it.
But their implementation...
No thanks. I'm not so pathetic that I'd need to use my hardware to
draw attention to myself while I'm using it.