And when you get there, you're overwhelmed with options:
Should I use this server? Or this one? What are the differences? Does it matter? Should I create an account on each of the servers I think I'd like? After all.. I can.. but is this how it's supposed to be used?
Well, what is each meant to represent? Should communities be constructed around the concept of topics, or should there be a server for each topic?
And please don't use any variant of "everybody can do it whichever they want", because this just avoids the responsibility of offering a personal answer and shifts it to them.
Personally I think the first (communities=topics)., while servers should provide voluntary redundancy for each other in case one of the servers has an inconvenient change of policies or circumstances for the users.
But I am not on the creative team of Lemmy, so my vision might differ from theirs. Also, I'm willing to change my belief if more solid arguments are presented.
This only states the multiple ways of how one can use lemmy, but neither envisions how one should use it. And vision is important for the non technical user, especially when exploring new grounds, because vision makes him go further. Not infinite overwhelming possibilities, technicalities and potential headaches. It's simple or it's complicated.
This seems to cine around to the topic of merging communities across servers
Definitely not critical. As you said, familiarity can be quite important in a genus-differentia kind of way. For me it definitely was: being familiar to Reddit I could think that Lemmy is just like it but better. Same with Twitter and Mastodon.