Probably a very polarizing question.
On the one hand, having most of the users and communities on LW causes technical issues (see this post), and also gives the LW staff too much power over Lemmy as a whole.
On the other hand, with 18k MAU on LW out of 47k (https://fedidb.org/software/lemmy/), every community listed there has a much higher chance of visibility compared to an alternative hosted on another instance
No. Half the point of federation is that not only communities (instances) can carry their own content but also their own culture. Posting or commenting about a soccer personality in, say, !spain@soccer.xyz is vastly different from doing it in, say, !soccerdrugs@news.world, even if the originating link to the discussion is the same.
I know, but this question is asked in the specific context where posters are mostly alone on a community for several weeks / months, where the LW equivalent has much more potential.