I am curious, what is the advantage to you foe doing this?

To me it just seems like a hassle, I have a Lemmy account, a Mastodon account and a Pixelfed account.

They all seem to have their own uses, and I guess I just don’t see the point of navigating Lemmy through a Mastodon interface…

But I am probably missing something here…

Sure: don’t use Mastodon to participate in Lemmy communities.

You can of course, which you clearly already know. Tagging a community in s top-level post even results in a good experience, but subscribing to communities does not, and you can’t vote.

Maintaining accounts on both is a good idea.