Why Head Tracking?

[imaca]

Have been curious about TIR, but just too expensive for something I probably wouldn't like. The only advantage to me is 6DOF.
A hat with modifier button can easily be set up to give 17 view positions operated with just 1 thumb, and (for me) is totally instinctive to use. Personally I would be more inclined towards getting a throttle with second hat to use for the other 3DOF.
The nervous system of the hands have the amazing ability to learn tasks, and then offload control of them from the conscious mind (as any musician knows).
By contrast, head control seems very awkward. I can't think of any other system (except for disabled) that uses it.