Literally was that Kbin started with the letter K, and thus matched with my going DE, KDE. So really just a matter of taste I guess. I always recommend people to use what they like.

I mainly just wanted to try Kbin after having already tried Lemmy before.

I set up both, and kbin was up while I couldn't get on world for 36 hours. Granted it turns out I had to just quit the app to get it loading but I didn't know that for a couple days and kbin worked fine

On top of elements already mentioned by others, an initial draw for me was the tenor of exchanges I was seeing on kbin. Of course the instances all interflow and I won't claim that Lemmy instances are not the same. But that was my initial experience. I like having a home base where there's some effort made to be communal and give thought out answers.