If your threat model doesn't account being forced by someone to unlock with your biometric then it is a good choice. It also prevents someone seeing your PIN which prevents certain types of shoulder surfing.

We do not support face unlock on supported Pixels as we do not think they are secure enough. The older generations had dedicated face unlock hardware the current Pixels don't have. 

Our second factor unlock will do a combination of fingerprint + PIN. That way they are two separate types of authentication (something you are and something you know).