This looks really cool! After building various logic programming engines on top of Janet: https://codeberg.org/veqq/declarative-dsls I was considering something similar (though more bare bones). I'd love to talk to the maintainer to discuss certain design choices etc. Maybe I can wrap it instead of SQLite and Prolog directly as I was thinking.

What would be a good use case for this?

I'm developing a similar project, I also added scripts to it so it works like an hermetic/replayable system too. Do you use yours for anything cool? Maybe a truth maintenance system of sorts? Do the queries get unwieldy at some point?