"But perhaps my thinking about it is too coarse, since iPad apps can be hybrids of both."
Right. How would your screen time limitation work if the screen was being used to read a book? And the book may be even more interactive than a traditional book. Then there's a line that can get crossed where the book has now become a game. But even then, if it's educational and informative as a book is, why limit that just because it's on a screen?
>And the book may be even more interactive than a traditional book. //
Books are not interactive. Isn't that the point, they're supposed to be entirely passive objects used solely to feed ideas to the imagination/consciousness/memory.
>why limit that just because it's on a screen? //
To encourage the child to develop interaction in the real world first.
Kids books often are. Many of my daughters favorite books have lots of flaps and pull tabs that make things move. Opening the flap on the third thing and seeing the number '3' or guessing which item is in which box based only on the shape of the box and then opening the box to see if you where right is endless fun if you're into that sort of thing.
Aren't they more like games in handy book-a-like format?
This I think promotes my point (I would!).
If you only ever share pop-up books, coloring books, sticker books, flap-books, texture books, carpet books (they have samples of carpet in them), etc., with your child then they're not being exposed to the central concept of receiving ideas from a passive medium and giving life to those ideas internally without a proscribed pattern as to how one should do that.
Mind you I've no strong evidence that the move through object presentation, to picture based story, to picture accompanied story, and on to pure prose, genuinely does lead to a development of imagination (rather than say just accompany such a development).
Aren't they more like games in handy book-a-like format?
Some, perhaps, but far from all of them. Most of them have the basic linear narrative structure of books and encourage the basic process of starting at page 1 and following the 'story' page by page to the end. The pop-ups and flaps assist in driving the story rather than replacing them.
Right. How would your screen time limitation work if the screen was being used to read a book? And the book may be even more interactive than a traditional book. Then there's a line that can get crossed where the book has now become a game. But even then, if it's educational and informative as a book is, why limit that just because it's on a screen?