It really illustrates, almost didactically, how for indigenous people (in this case, obviously, we are speaking of Australia, but it's the same with other places) the world right now IS the 'dystopic future', they are living in a post-apocalypse society.
The way it's written and the subvertion of expectations is what makes the book worth it, because the story per se is nothing new. I did find it a little too depressing, but... realistic.