amulet
n.
An object worn, especially around the neck, as a charm against evil or injury.
n.
Some object superstitiously worn as a remedy for or preservative against disease, bad luck, accidents, witchcraft, etc.
n.
An ornament, gem, or scroll, or a package containing a relic, etc., worn as a charm or preservative against evils or mischief, such as diseases and witchcraft, and generally inscribed with mystic forms or characters. [Also used figuratively.]
Wordnik from The American Heritage® Dictionary of the English Language
Some mask wearers have to wear them because of work, visiting with family in hospitals/nursing homes, doctor visits.
Some are stupid.
Others are drama queens who would cartwheel naked down Main Street if the gov't said it prevents covid.