If you mean Lemmy: Lemmy is an open source and decentralized alternative to Reddit.

If you mean /c/boost, it gets federated to my instance.

Not being FOSS disqualifies any lemmy client for me, I dont want a client that undermines what I like about the platform.

If I want to microblog, I will use Mastodon.

And even if a lemmy community bans self promotion, just create a spinoff community for people to show off their content!

Yes, also what could possibly be the alternative? Federation but with unique community names that transcend what instance you’re on? What would be the point?