When students are focused on themselves, applications can be distracting from the math concept. The social interaction takes over and the student wants to get attention. Projects and working together can increase this as students pay attention to each other.
If there is no real concept in the math lesson, it is really just drills, or self discovery of a latent concept that is not really revealed, or several of them cooperating, then the student never gets the fundamental math in the activity.
Thus the application acts as a distraction of the student’s already distracted attention. The student is distracted by himself, by other students, and by the application. The math concept is likely not even taught in a foundations sense. So the student gets nothing out of it except a drill at most.