Yes, it really does!
Since my post yesterday, lemmy.world has added about new 2600 users, bringing the user count to 28361 users. It's the clear second-largest lemmy instance out there and quickly closing in on lemmy.ml's 36k users (not taking new signups).
Interestingly, third-largest lemmy instance beehaw.org seems to have lost about 275 users since yesterday. Guessing some people were pissed off about its defederation enough to delete their beehaw accounts?
Some might argue that one instance dominating is against the whole Fediverse idea, but I disagree here.
Big generic beginner-friendly instances are needed. When users first come here, mostly from Reddit, they have no clue how federation works, and telling them to join mostly empty instances isn't really helping them. Instead, the advantage of big instances is that at least, even if the users don't get the federation concept yet, they'd still have tens of thousands of local users with whom they can interact until they naturally figure it out themselves.
Think of it as the equivalent of having Gmail and Hotmail in the email space. They are huge and are clearly dominating the email space, but they also serve as decent entry points for users who will then later maybe find the time to look for more options.
The fact that Lemmy can federate is an advantage on its own, even if in practice we mostly don't. A federated Reddit wouldn't have had to resort to the blackout; users could have spun up their own instances, defederated from the central instance, and carried on, cutting the problematic management out with very little actual loss to the rest of the community. Even if a single instance ends up dominating, the possibility of federation is a big win for users.