Head look controller not supported on iPhone?

Unity Engine
,
1

Does anyone know why the head look controller isn’t supported on the iPhone?

2

I just wonder: what is a head look controller?

3

You can read about it hear.

http://blogs.unity3d.com/2009/07/10/just-looking-around/

It’s very useful, but if you download it from the asset store there’s a note about how it’s not supported on iOS/Android. I just wonder why.