It's possible that she didn't read it; she could have been busy, or a lot of interviewers don't want to have preconceived notions about the applicants before meeting them. For those who do read your app and ask about your ECs anyway, I think this is mainly to evaluate your oral communication abilities.And don't forget to completely review your application before your interview. One of my interviewers told me she had not reviewed it and proceeded to ask me questions that she could have easily read the answers to (like what extracurriculars I was involved in during my undergraduate years - 10+ years ago)....I'm still trying to figure out if she did it just to rattle me or if she really had not looked at all.
This was a big one I got drilled on. Followed by a "What made you decide on (vet) medicine? Did you just roll out of bed one day saying 'I want to be a doctor?' "And as a nontraditional student, in addition to why medicine and why this school is why now? I must have been asked about 10 different ways (in the same interview) about why I am pursuing medicine now (isn't it a big leap from what you're already doing? How do we know it's not just a whim and that you're serious about it? Have you thought about the sacrifices you'll have to make? etc.)