when someone is not fully afk (away from keys). that person is busy but keeps in touch with his device less then often,so thats when you sound it like that you are semi-afk.
With wireless headphones, when you are in a remote meeting you can mute and walk away to take care of any personal needs. Or you might just be in the next room but you have the audio being played through speakers loud enough to hear. So not only are you away from your keyboard but you are also still listen.