Mostly just fun, with potential for learning
This could be a personal problem, but my students did much more playing than learning with the app. The learning is kind of optional because you could just choose to play around with animations and graphics without actually paying any attention to the whole story arc idea. It was difficult to keep kids' focus on meaningful storytelling when they were mainly interested in just playing with the app. It was also not so intuitive to figure out how things worked, and some students got frustrated.
How I Use It
I don't really use it in teaching anymore. I tried using it to help students bring out their storytelling skills as a prelude to writing, but it just took too much time without enough visible benefit to their target skills. I might continue to offer it as an optional activity for a bonus after completing work, but I no longer have time for it in my actual lesson plans. Too much time was spent on things like adjusting the characters' sizes and things like that.