I've been using the beta on Android for about a week. It gets updates constantly, sometimes multiple times a day. Keeps getting better and better.
I’m using the iOS beta right now and really enjoying it. It’s working through kinks but very promising. I believe the dec said Artemis will support Lemmy in the future too. It would be awesome to have multiple platforms in one app.
Someone is working on Artemis app (closed beta), that's about it. Kbin lacks API apps can use.
App development will probably be slow for a bit. As others have mentioned, Artemis is in development, but because Kbin doesn't have a public API yet, I believe that Artemis is having to use their own web scraping method as a stop-gap until the API is released. I imagine that's probably a taxing process for the dev's server to handle, which is probably why the private beta is having such a slow rollout.
Once the API goes live, I imagine there will probably be several apps that pop up pretty quickly.