You might receive a discount at the PPH (or the other Disney properties), but that's not necessarily guaranteed. I think there are only a limited number of rooms at the AAA rate.
You also can get 10% off dining at Goofy's Kitchen, and possibly other character dining locations. You can get a 20% discount on Walk in Walt's Footsteos tour. There are additional benefits if you book a vacation package (hotel and parkhoppers) through AAA