I didn't see kbin.social in the list of instances when logging in, and when typing manually, it returns an error. I'm still learning lemmy - is there a reason kbin login doesn't work?
Anyways it hardly matters, this acct is fine too and the app is amazing. Perfect timing with RIF now returning Error Forbidden while logged out (officially dead, rip).
Because kbin isn't Lemmy. They're different applications that use the same interconnection protocol (ActivityPub) so the subs and posts are shared but they are different. Lemmy has a mature API and several clients. Kbin is only available through a browser, their API is still on development or testing there isn't any client yet and the only one known, Artemis, is in closed beta.
OTH kbin supports mastodon tweets not only Lemmy posts.