You may not, however millions of teenage girls do. She's basically a way into more mature fantasy novels for many pre-teen/teen girls (and boys) and their parents. I can tell you it sparked an interest in other dystopian future sci-fi/fantasy in people I know who wouldn't touch such stuff normally.
I think you are overstating it's popularity. It is not like it is on Harry Potter levels of popularity. It's just the new "in" thing.
I saw the movie and generally enjoyed it (nice to have a female hero) but it is not influential compared to some of the other things on the cover. It's been around too short of time for that.