I think I have an idea of how it might not support audio books. What if audio books had the following issue:

> There is a very noticeable pause between each track that it plays, despite the entire thing being queued.

> That pause is presumably also present when playing music, but no one notices because each song is its own track. Audiobook tracks split in places where a pause would never occur naturally.

It would almost be like it wasn't really built with audio books in mind, but was rather designed around music.