"Essentially, for the users, it means that an account for site A can be used to login on site B because site A and site B trust each other"
And what if site B takes actions that no longer make it trustworthy to site A?
One more damn thing instance admins are going to have to monitor to prevent damage to their users
How about if we don't do "single sign on" and people just get over the "Mastodon is too harrddd!!!" trope?
Maybe?
Nah
That'll never happen
The "One Fediverse To Rule Them All" crowd is just too influential
cc @1984