[RheingoldRiver]

> you are forced to always go forward in your "reading", so your opportunities to trace back to a hard concept or even pause and think about a sentence for a while are close to 0

my earbuds have a double-tap to play/pause. What makes you think I don't use it??

> but if you were trying to improve your comprehension of language by reading harder books, or trying to study actual concepts, audiobooks would be useless

reading is reading. For nonfiction where my goal is to learn I do audio and pause to take notes. For entertainment I read speculative fiction usually as audio-only, sometimes also with text (Malazan and Terra Ignota being notable for when I wanted text). But that doesn't mean that what I listen to with audio only is somehow lower quality.

And it's kind of funny to me that you say "improve my comprehension of language" because I listen to audiobooks somewhere between 3.5x and 4.3x speed generally (and still working on improving my comprehension at higher speeds). You're probably going to say that this necessarily means I don't understand what I read but...no, actually, listening to audio has drastically improved my language processing ability. And even if mostly I'm listening to fiction for entertainment, this improvement in comprehension carries over to reading nonfiction.