I agree with everything you say. Personally I work on mobile apps for a living, but our family does not own a tablet and we seldom allow our 2 daughters - ages 1 and 5 - to use our phones.

But! As a parent, there are times when you need to distract the kids for a few minutes. My main goal during those distraction times would be that they are distracted sufficiently, and enjoy themselves. If they happen to also "learn Algebra", well I don't really have a problem with that. So I see this as something that is probably worth having on a tablet instead of the completely made-up-off-the-top-of-my-head Disney Princess Tea Party App.