I think the fingerprint reader could work great with iPad, as that device is quite often shared with family members. Each user could have their own profile, which the iPad would automatically load based on the fingerprint. So when you press the Home button, you're taken to your own unique home screen with your own apps.
I didn't watch yesterday's presentation, but I did watch the IOS 7 announcement a few months back, and I don't recall seeing any mention of multi-user support. Did I miss it then, or was it referred/implied yesterday ?