Now why could you not use a rotary knob (momentary type if need be) same as a switch, no reason simple as that. The likely reason they are using a switch is lack of real estate. There is very little room behind the bezel with the rotary HVAC controls in the way. From what I understand they have tapped into the board of the OEM rotary HVAC controller to add the switch. So you are not getting just a blank bezel it also includes modified OEM hvac controls, hence the hefty price tag or one of the reasons. What bugs me is they found the way in add, why not add the rest of the controls?? And why such a fugly switch?