Before unlocking for the first time, after too many failed attempts, and also at regular intervals, you have to enter your PIN/password if you have activated fingerprint recognition. It's a great security feature in itself. I would also love to have this feature for PINs, so that I have enhanced security without always having to enter an x-digit password.
And yes, I know that this is more about owning vs. knowing, but it would be very helpful for users in general to be able to implement increased security there as well.