The TSA has attempted to roll out more facial recognition in airports but has so far been blocked from doing so. Clear is stepping in to gather all that biometric data for them, in addition to the fingerprints and Iris scans they already have, and provid it to TSA directly while making a profit on the side from doing so. 
“In the near future, Clear’s new facial recognition system will electronically transmit members’ digital identities to TSA’s second-generation Credential Authentication Technology (CAT-2) scanners, Clear says.”
https://www.cntraveler.com/story/clear-at-airport-facial-recognition
It’s not legal for the government to take it. So instead, we’ll pay to give it to them.