(I suppose there is some sensible reason for a mailing list server to retain human names, but it escapes me at the moment)
Here's an example: A club list where the list manager wants to know which club members are on the list, and which people on the list are not (current) club members - since people often have multiple addresses and will sign up for an email list at a diffent address than they supply the club's membership director. Or a list for club or organization directors & officers, where it's way easier to scan the names to see if the appropriate people are on the list than to memorize everyone's email address (esp. when half the people seems to prefer email addresses that are variations on "diver" rather than using their own names). Oooh, I hope I'm not upsetting charlie's delicate ego by daring to offer a thought . . .