Fingerprint sensors work in the dark. Facial unlock doesn't.
Edit: looks like I'm probably wrong on this one
Edit: looks like I'm probably wrong on this one
Facial Unlocking isn't just using image recognition. Face ID, specifically, using point mapping across a face, creating a 3D map of the face and reference points to unlock the device. I don't think a flat 2D image, even with IR photography, could trick a system like this.
A Hollywood grade prop mask of someone's face might be able to trick it, but that seems like a huge outlier.
A prop mask is one approach, but adversarial machine learning techniques might be even more effective, especially if you can study the adaption to a particular face.