But I mean, already lots about the buzz caused around the Fediverse nowadays only EXISTS because Meta anounced to join
The most obvious thing is: scale. With matter, ActivityPub is finally tried out on a bigger scale. If a global, big fediverse was the goal, this was always one way how it could go. A big player is joining and then, the Fediverse in turn grows and grows with it; just like with the WWW and AOL. What’s your alternative to this?
Or don’t you want the Fediverse to become a big, global thing where everyone has a Fediverse account and so on?