One can follow Lemmy (and I presume Kbin, though that I have not tested myself) communities directly from any other fedi instance. For example, I am following @technology directly from my account here.
Now that Lemmy/Kbin have become pretty active, this might be a decent way of getting new fedi users to have a better on-boarding experience.
Just suggest a few active communities to them, and bam, plenty of interesting stuff gets boosted into their timeline. 🤔