Some of us do not like audio books
because of the interpretation and dramatizations of the narrator, as well as the inability to use other functions available in text ebooks.
Listening to TTS is more like reading a book; we only hear the words, with just enough inflection and pauses to capture essential punctuation.
It is indeed bland, but that neutral delivery is what allows us to use our own imaginations and hear the voices and emotional states of the characters as we will, without interference. That's the best part of reading books, to me.