Heh. I have to admit that secretly I already knew what it is for, and the initial post was mildly troll-ey.
The thing is though, the lightbar just seems like a totally unnecessary thing; apparently tracking movement wasn’t possible in any other way than an intrusive light emitter that drains my battery and reflects on my tv. Plus, if you never use PSVR, like me, it becomes even more puzzling and counter-intuitive; sometimes it’s blue, sometimes it’s yellow and sometimes it’s red. “Does red mean my battery is low? Or does it mirror a theme in a game or my UI? No surely it has to do with which player I am.” Anyway the touchpad is similar. At least it’s not in the way like the Vita’s, but I’d rather just have a start and select button. It all just feels like it’s “innovating to be innovating”. And that’s gimmicky.
Not that Sony is the only offender, I don’t see the point of the Switch’s ‘HD rumble’ either. But I digress, I’ve said enough times what I think about the Dual Shock controller as a whole, you guys don’t need to be annoyed with that here. Some days, I’m just, ‘in a mood’.
The lightbar color can be messed with by the devs.
They can choose to make it blink or change to any color they want, based on what's happening and what you are doing.
I remember playing Bastion and it would turn green and I thought: damn, the devs are trying to push me to the green side of the force inside my own PS4!
I think it presents different colors while on local multiplayer too, to easily set the controllers apart.