It's still useful. Some friends and I send group email (each person listed on the To: line) to manage our D&D game, but since it's only about eight recipients

It's still useful. Some friends and I send group email (each person listed on the To: line) to manage our D&D game, but since it's only about eight recipients, it never gets out of hand and we're kept up to date with who can make the game and who can't. What seemed to happen in the article is an email sent to a group-id (single email address that the server expands), not a list of a thousand-plus individual email addresses. To the client, a group email address is just an address---there's no indication that it will go to a few thousand people.