This is probably the best documentation on Adobe AIR touch support:
http://help.adobe.com/en_US/as3/dev/WSb2ba3b1aad8a27b0-6ffb37601221e58cc29-8000.html
Midway through that page it states:
Note: Listening for touch and gesture events can consume a significant amount of processing resources (equivalent to rendering several frames per second), depending on the computing device and operating system. It is often better to use mouse events when you do not actually need the extra functionality provided by touch or gestures.
The only benefit of touch, I would think, would be multi-touch. The TouchEvent has a touchPointID which allows you to track the movement of each touch point. If you don't care about multi-touch, it sounds like Mouse Events would be the way to go.