I can't think of one single practical use case for this that would benefit my life, because, right behind the glasses I have my very own locally available facial recognition built in.
I have a similar thing with names when and I think it's just because my brain somehow decides that interaction meant nothing and the information was not important to save.
3.08%, according to https://hms.harvard.edu/news/how-common-face-blindness
I hung out with a large group of people for nearly a decade and couldn’t remember who was who until the pandemic. The names under zoom helped me gradually learn over weeks.
When I teach scuba I recite the list of student names for my class in as random an order as possible while I drive to the shop to lower my cognitive load to put faces to names. When I do roll call, I write down every person’s name and try to gradually move off the cheat sheet as I call on them to answer questions. But once they put on their gear (especially since I teach where they use hoods) it all goes downhill. Two white guys approximately 35yo? I’ll get them confused.
If this were socially appropriate I’d totally use it as my prescription glasses to help continue smoothing the curve.
Secondly, put yourself in the opposite situation, do you really care if someone forgot your name? Does it even reflect how well you know someone? I had a friend at scouts when I was a kid and we were inseparable for a year. Never remembered his name. Didn't matter.
(not that i think meta is doing it for accessibility reasons...)
At least where I've worked, there's a constant churn of care staff — with some workers bridging a gap for only a single shift. Institutions currently offer a printed list with portrait, name, room number, and relevant pathologies for each resident. But it takes most people at least a few days to memorize the info. And some people are difficult to recognize from their intake photo.
OTOH, the tech would only need to match a handful of residents. And it would need to conform to privacy laws. So doing the match locally on the device would be a much better fit.