Well for example the historical context of the book, what the author is trying to say, the symbolism of the characters, etc. I loved asking it questions like "considering the historical context of the book, and that character X symbolizes Y, what did X's action mean and what was the author trying to say?" I think I got a much better grasp of the characters and the bigger picture of the book this way.

And yeah it sometimes gets things wrong but I can always supplement it with googling and my own knowledge of the book.