With Mastodon and other microblogging software it makes sense, since the primary focus on those media is identity. You create a persona, you create and distribu

With Mastodon and other microblogging software it makes sense, since the primary focus on those media is identity. You create a persona, you create and distribute content. With Lemmy that's not the case. It's about sharing information and discussing it. So federation is less crucial, but it does add one powerful benefit: the network itself can have network effects and grow to critical mass, leveraging the same benefit Reddit had over disparate forums and the like. It's not a necessity from a user perspective, but it makes it feel like all the information is in one place and so users prefer it anyway.