They're probably referring to the optional facial recognition based boarding systems that many airports in the US are rolling out, primarily for international flights. It uses facial recognition to match you to your passport photo based on the documents verified during check-in, to ensure the person boarding the flight is the same person who checked-in when their documents were manually verified and recorded in the computer system.
You can still hand your passport and boarding pass to the gate agent, it's not required to do facial recognition boarding if you don't want to, and at any rate it's not doing an iris scan, it's using a standard facial dotmap to match to a photo. It's not even doing 3D mapping, because it's source material is a standard passport photo.
You are not. There are three different programs by which you can accelerate entry/re-entry to the US and all three rely on facial recognition. All are optional.
There is no facial recognition in the normal re-entry line (and all these processes are before customs as part of border control). Foreigner entry may now require facial recognition, I’m a US citizen so don’t experience the process foreigners go through.
