Of course it is required. I'm not saying that. I'm saying because the device has both sensors in it, which the camera DOESN'T track and light bars, which the camera does, to create motion on screen for some non gaming apps may not require the light bars. We don't know what those are yet.
The problem here, which I was trying to clear up, is Menace thought that the motion of the headset was and could only be made on screen because of the light bars. I honestly think he didn't know that there were any sensors in the controllers/HMD. So I had to go through a range of differnt instances where previous devices supported a similar tech (I forgot the Vita).
Yoshida says that the device requires the camera, which is absolutely true since the majority of its use will be game or game type application. However, this may also not hold true if a non game app releases that only uses it sensors rather than the sensors and the light bars. It has happened more than a comfortable amount of times in the pass to support this theory.
I do know Sony is gearing up to launch its new virtual, social world in a few months, and it is said to use the HMD. Because this is technically a game, it may require both the sensors and the light bars but then again, some apps/tasks may only require the sensors. Again, we don't know yet, but its most certainly possible as the pass has proven.
The problem is you just can't answer the question, yes the camera is required, that's all that was asked, not how the camera is implemented/used.