I think it would be awesome to have some sort of Achievement/badge/trophy system just to give you goals to reach for and other fun things. Like you could get one for…
making your first ace
playing a round with 4 people on the card
playing the same disc course multiple times
Getting a round in every day for a week
Playing out of state
Playing an event
You could also push the other things you can do on the app with this as well like…
putting practice
measuring throws
Accuracy practice
Adding a course to your wishlist
Adding discs to the app
Adding a friend
And stuff to help the app in general
Adding reviews to courses
Adding a new disc shop or course
Adding an event