Because it's gimmicky and not useful?
Reviewing pictures with pinch to zoom and drag to pan would be a HUGE improvement over push zoom button, scroll dial to zoom, nudge around joystick to pan.
In fact, I would say it's analogous to when Google Maps introduced mouse scroll to zoom and drag to pan. Do you remember what using Maquest with its zoom slider and navigation arrows that you had to click was like?
I don't care about the settings aspect.