What about for people who don't have an imagination? Is there no difference between watching a movie and listening to an audiobook for them?

Everyone has an imagination. Some people have had it beaten out of them or were never taught to pay attention to it or use it, but everyone has one.

This is not true. I and many other people have aphantasia[0], our brains are simply unable to imagine visually the way other people are.

[0]: https://en.wikipedia.org/wiki/Aphantasia

Fair enough; I shouldn’t have said “everyone” because that’s obviously not true, but only pedantically, for the most part. It’s not insensitive to say “everyone has a nose” and mean “except the very small percentage of people that don’t have noses due to birth defects, trauma, or genetics”.

1-3% of people have aphantasia. That’s not everyone, but it’s close.

The question remains.

Throughout my life, I thought "mind's eye" was a metaphor, and that people didn't actually see images in their heads. When I discovered aphantasia was a thing, and that I had it, I also accepted it was rare. But turns out, about a third of my male friends also have it. Not one female friend has it, though. It's a pity there isn't much research on the subject.