Great for discussing imaginary friends and why some kids have them. If we need to comfort ourselves by having imaginary friends, why not have them large and pink and enjoying themselves doing all sorts of things we normally can't do?
It's also great to have both the first edition and the the "censored" later edition for comparison. In addition, it's a perfect example for discussing censorship of young children's stories, why they happen, and what the effects may be.
Rather than say the author should not have written about the daddy smacking the girl, or that the mummy was on diet, it would be healthier to talk with kids about what they think and how they feel about the events in the book, and help them process those feelings. We mustn't forget that even when we successfully get authors to delete certain things from their stories, or withdraw their stories altogether, we can't change what's really happening in the world. Is it better to not let our children know about real things at all by never mentioning them or never letting them read about such things (only for them to get a rude shock in life, eventually), or to let them learn about them through their reading, and be there to help them process what they find out through books, and thus indirectly prepare them for the real world?