I’ve never joined the SAR, but while doing genealogy, I found an online copy of a multi-removed cousin’s letter from the organization, accepting him in, circa 1900, same ancestor involved. :^)
I did it just to have a record on file that goes back a bunch of generations. So anyone later doing a genealogical search will quickly get answers.
I tell people to get this done in couple generations people will be buzzing off to the stars. All of the couple hundred years will look like some jungle enshrouded mayan civilization that’s come and gone.