Man I wish Plex, Netflix, Prime Video, etc., had this feature. It's awesome.
Also, and only tangentially related, how much shit do you think that kid gets over his name in school?
It does the same thing if you use the Chromecast version. It will keep showing what actors are current on the screen and also show what song is playing.
Man of Steel?
The feature has been around for about 5 years ;)
( https://ccm.net/faq/30199-google-play-movies-tv-now-integrates-a-facial-recognition-tool )