Apple says HomeView can recognize up to six different people to deliver a “personalized experience” for each user.
John Gruber at Daring Fireball has more details on how HomeView’s facial recognition feature works.
HomeView’s face recognition support According to Gruber, a user must have a “registered personal device” with Apple Intelligence support in order to be “recognized” by HomeView.
Your first question might be how this facial recognition to identify users works, using a Center Stage camera alone, when other products (like, notably, the iPhone Duo) don’t let you unlock using the camera alone.
This means the Apple Watch does not count as a “registered personal device” for facial recognition on HomeView.