I suppose regarding children's books I should have tempered that with "all children's books". There's a category of children's book that provides a tactile experience that ebooks/apps cannot match (e.g., "The Very Hungry Caterpillar")

(FWIW, you can get a "The Very Hungry Caterpillar" app, but it's a different experience, being an interactive toy. Not worse, not better, just different. It appears to nicely complement, not replace, the book.)