While Apple use of the tracking was not more than a party trick, the foundational technology they created for this is currently the best low budget tracking solution and heavily used in VTubing (online streamers that use an Avatar with live facial tracking instead of showing their face via webcam)
Are these the Memojis or whatever Apple calls them these days? Pretty much eveyry iOS update mentions them near the top of the list and I still have no idea where to find / create / care about them...