Exactly. I seem to remember an app a while back that was billed as a heartbeat reader and it would have you repeatedly press and release the fingerprint sensor.

Exactly. I seem to remember an app a while back that was billed as a heartbeat reader and it would have you repeatedly press and release the fingerprint sensor. After a delay it would flash some sort of in-app purchase authorization. Pwnage that relies on some sort of user interaction is worth 50% less, and rightly so.