Apple has released iOS 9.3 beta 2 to developers for testing. The second beta brings various improvements including a new Control Center toggle for Night Shift.
iOS 9.3 adds numerous new features to Apple's mobile operating system including: Night Shift, secure Notes, more personalized News, an improved Health app, updates to CarPlay, and new Education features. More details on those features here.
I think it is the most easiest feature to use. It is similar like the auto brightness feature. I know that, Apple introduces this feature to ease the strain on your eyes when looking at the screen at night. I really appreciate this initiative of Apple. I don't like this orange color screen. That's why I choose "ocushield" screen protector for my iPhone. Which protect harmful blue light and also helps me to sleep better.