Mercedes has a good demo video about current state of this tech (EU only) - when you drive a car with it, it’s literally magical. Alternative tech uses a projector-like screen with 4K resolution, allowing for very precise light control.

Here is a demo: https://m.youtube.com/watch?v=0OJjvYPV3oc

Current resolution generally seems to be less than 100 headlight 'pixels' so we may need more resolution before we can dim someone's face specifically.

But that could get especially interesting when you connect it to a self driving system. The car's AI could become a more active participant in 'looking' at things.

With RGB LEDs it could highlight them in a different color; the Fox Puck of driving? https://www.youtube.com/watch?v=grOttsHuuzE