I find my phone much more comfortable to hold than a book. It fits my hand.
You only read one sentence at a time anyway. I rather scroll, keeping the current sentence in the middle of the screen than jump around with my eyes in an open book, and having to turn pages, or keeping them flat.
Am I missing something? (Real question. I read a lot!)
Nah, I'd say most digital books are probably PDFs.
Not how I read when I read on paper & this bothers me on a phone a lot.
I'm not functionally dyslexic, but all the words pop out at the same time, you could say I read verbs, then tense, nouns after and then I read adjectives in a sentence.
But English is also my second language, so my first language's grammar probably fits closer.
Oddly enough when I first encountered lisp, the nested pile of map, fold and filter was easier because of the well trained habit of restructuring after reading verbs.
1) Some books have images, charts, tables, etc. The screen size makes a big difference for these.
2) The format of the "book". Reading a PDF for example is much better on a bigger screen.