Listening to books is just too slow. For the right kind of book with a slower narrator, I might be able to listen at 2x or 2.5x and still understand it. But why not just devote my full attention, read it at 8x and probably have better recollection than from passive listening?

Other books require more work and I probably read at 1x speed with frequent pauses and re-readings. I'd never understand those if they were audio.

The one time I might go for an audio book is when outside exercising or commuting, but that's when I listen to music or podcasts.