Phone unlocking with face-recognition technology was never a secure option to opt for, Android phones had the feature as early as 2011 and latest as 2017 but both got duped easily as demostrated in linked posts.
When Apple announced iPhone X with various sensors for FaceID, it was assumed it could not be that easily fooled/hacked, but the it turned out the otherway. There are now multiple videos shared by users where siblings, kids and hackers/researchers are getting a free pass on users locked iPhones without much efforts :(
Do watch the three videos shared below where the mighty Apple iPhone X flagship gets pwned by siblings, kids and researchers in seconds.