FaceID is not required to unlock your phone. From Apple's FaceID support page in the Privacy section: https://support.apple.com/en-us/HT208108 https://support.

FaceID is not required to unlock your phone. From Apple's FaceID support page in the Privacy section: https://support.apple.com/en-us/HT208108 https://support.apple.com/en-us/HT208108 "If you choose to enroll in Face ID, you can control how it's used or disable it at any time. For example, if you don’t want to use Face ID to unlock your iPhone, open Settings > Face ID & Passcode > Use Face ID, and disable iPhone Unlock. To disable Face ID, open Settings > Face ID & Passcode, and tap Reset Face ID. Doing so will delete Face ID data, including mathematical representations of your face, from your device. If you choose to erase or reset your device using Find My iPhone or erasing all content and settings, all Face ID data will be deleted."