[aaimnr]

Books are not distraction machines in the sense phones are. Book may be a distraction from something else, but when you are already reading a book, you are concentrated, attention is stable and all cognitive faculties are being trained in positive direction (keeping the whole story in mind, imagining the plot etc.). Phones, on the other hand, are distracting you while you are interacting with them. Attention is switching constantly between apps, even within a single app you may be constantly swiping through content in order to get gratification. In this mode you're UNLEARNING the stability of attention, that books help develop. There may be specific apps and games that cultivate concentration as well, but the way the average kid uses their phone is definitively detrimental to their mental capabilities.