the live vision camera where you can see people on Xbox Live or the Microphone, so you can talk to them on Xbox Live.
Isn't the mic on the headset?
the mic/headset is a must for online gaming. the vision camera is only supported by a few arcade titles and R6:V, but only to have your likeness attached to your customized character.
and private chat
you can also use the Live Vision Cam for web chat on your PC
microphone if you're into online gaming...communication is a must in most games that are team-based