Lemmy is also a lot older than kbin - kbin is only a month or two old, iirc, and it’s still technically in beta. I’m sure once an API of out for it, we’ll start seeing a lot of apps popping up. It just takes time - we’ve only just in the last few months seen a boom in quality Mastodon apps.
I’d say that in about six months, we’ll be spoiled for choice.