The fact is that she's got a crush on Harry - an aspect barely acknowledged in the film, and then only when he first arrives at The BurrowTwice actually if you count Draco Malfoy's teasing about Potter having a girlfriend when she sticks up for him.
They also did a good job of showing Lucius Malfoy's "slipping of the mickey" so to speak in a way that is shown outright, but not obvious at first viewing. Brian DePalma pulled a similar stunt in Femme Fatale, but his distraction was much more distracting.
Regards,