As a web developer and a parent I do not see the benefit of introducing distracting apps to children. The kinds of apps i have seen used with my daughter's class so far have been much less efficient than simply looking at a book or using flashcards. They increase the child's cognitive load by introducing game elements and other bells and whistles. Learning time should be as efficient as possible so that children can PLAY efficiently as well. And they need to use that time to play OFF the screens.