It seems most "worth it" if you will
--participate in Jedi Training, Enchanted Tales with Belle, and/or Pirate Training (in MK, I forget the exact name)
--take lots of ride photos (less likely with the ages of your kids)
--do lots of character greetings (it's perfect for this, since Mom & Dad can put away their cameras and just enjoy the interaction)
--stop frequently for family shots in the parks
When we went in August, we did all of the above, and it was definitely worth it! We ended up with over 400 pictures in our account.