1) Starts as protection against infection, pollution
2) Then privacy, to defeat face recognition
3) Then people realize: less time on makeup, hair
4) Eventually, standard piece of clothing. Both privacy and hygiene.
theatlantic.com/health/archive…
For people to truly be pseudonymous, they'd need to cover their face in public & reveal only to the trusted. Tech like cvdazzle.com did exist, but this is how it goes mainstream