That's how I know 12 year old kids are communicating to their mother's—who must be over the other side of the fucking house—about Callum, their little brother, being annoying and wanting to have a go. Just listen to him, Callum. You can watch now and have a go later; it's not your turn, jeesh.
It’s pretty common for headsets at least to have light on = mic off. Makes sense for a communications device since the default mic on makes sense but I agree it doesn’t make sense on a controller.