[MargaretR]

An audio book is akin to 'storytelling' which was in regular use in the days before populations became literate, and was the way that history was related to later generations.

I spend most of my waking time reading - webpages and (paper) books.
This can result in eyestrain sometimes, so I find it convenient to give my eyes a rest by listening to an audio book or radio dramas.

All three - paper, audio, and ebooks - are equally useful.