Why wouldn’t we? They invest hundreds of thousands in good UX and novel business models and are one of the most popular online platforms at the moment. Better borrow liberally from what they and other companies like it come up with to make f/loss better and more financially sustainable. The joke is that because Discord took VC, their server boosts will actually not be profitable enough for them. But it might be for fediverse platforms.
I am also not promoting “one model”. There can be many, this is about allowing customization and having communities and instances reflect contributions by members. It is fairly successful in the proprietary space no reason not to similar modes of sponsorship and reward in open source.
These are good features but I would be very careful calling any of this privacy. You can call it “limiting discoverability” and emphasize that it relies on parties (whether google or kbin) to play ball. In essence the posts are still public, can still be found, can still be linked to but are just not as discoverable as other posts.
Just to chime in, https://lobste.rs/ also uses a tag system which is quite nice.