There's no doubt about it: exposure to fiction is essential for developing children's imagination. In a way, it matters less whether the format is listening to a book, reading together with a parent or reading by themselves, just as long as they get lost in the imaginary world of book characters.
We usually include e-books and online reading in the same set: as long as it's a book, it doesn't matter whether it's on paper or on the Kindle. However, as early as 2006, an eye-tracking study by scientists at the US-based research group, Nielsen Norman, indicated that people read web pages and books on iPads in an “F” pattern. This means that they scan the top line all
the way, then halfway across the next few lines, and then only down the
left side of the page, all the way down to the bottom of the article.
This kind of reading is helpful when we're trying to form a quick overview of the text (non-fiction reading), but it doesn't work to yield a deeper
understanding of what we’re reading. Wall Street Journal had this to say: "as much as rich multimedia-laden content captures our attention,
with a mixture of words, sounds, and moving gifs, videos and image
galleries, studies have shown that together they can lead to lower
comprehension than just reading plain text."
Something to ponder, for sure, especially if your Learning Style is visual.