I'm going to say that yes, audiobooks give you almost all the benefit of reading the book. You are getting something in full detail, not "made for the screen". When something is adapted for TV, a LOT of detail/depth has to be removed OF NECESSITY or it just wouldn't work.
Think of it this way: LISTENING to books is how many people used to "read" many years ago. And St. Paul did say, "Faith comes by hearing" -- not by watching snazzy Youtube, VHS, or DVD videos.
One of the devil's biggest accomplishments is to damage the world in such a way that the majority of the population can't (or don't want to) read a book. How will they EVER be converted?
Multi-media just can't save souls, unfortunately. It needs more depth than that -- books, sermons, etc.
St. Paul was right -- Faith comes by hearing.
Matthew