Oftentimes, the audio description doesn't match up to the sound because that sound would impede hearing the description. For example, in one of the Batman movies, the audio description was something like "Batman punches a goon" or "Batman pries open the door with a concealed device in his hand". The exact moment that scene occurs is usually quite noisy, and would be difficult to hear the description.

Almost everyone I know uses audio books for any extended period of reading. Keep in mind that Braille cells have to be a certain size, so books end up becoming quite large. For example, this is roughly what the Bible looks like in Braille.

https://i.pinimg.com/originals/71/dd/0e/71dd0ecd0b9f5f9c8f81a276c616c52f.jpg

http://www.compassbraille.org/images/stories/compassbraille/braille/43volumes.jpg

Conversely, an audio file on an iPhone has virtually no weight, and you can hold a great number of them on your phone. It is significantly easier to pull out your phone and headphones to listen to something, rather than carry a phone book sized book.

So, I will answer one of them, you got good answers for the others and I don’t use those often. I don’t watch movies with audio descriptions, I either watch them without or not at all. And I don’t listen to audio that much.

I would say my preferred medium is braille but by a braille display. I don’t read audio books wel. I don’t tend to pay attention to the details there. I just gloss over and listen for the main ideas. So if I really want to do that book any justice I read it.

Yeah, a braille book can be large. My favorite comparison is of the bible. Go look at one, I don’t care if you are not religious. You know what a regular bible looks like right? Well a braillebible takes up three shelves of a bookshelf or three levels. So, it’s huge. Imagine 20 books of a size of a family picture album. That’s a bible for us. Quite portable no? Wouldn’t you just love to carry one of those bibles to church with you?

The answer already given to your other question about audio description in movies is correct so I won't rehash it. As far as a medium devoted to audio narratives, it exists. It's called audio drama or radio drama, I like it myself and I know it has some blind fans. As far as visual descriptions in books, yes if the author is going on and on about the colors of things it can turn me off. However as someone who was born completely blind I think visual descriptions in books have also helped me understand things from the sighted person's perspective.