I have used janet for embedding into another program as an alternative to lua and it was great for that case. Lua doesn't have good tooling either, and I didn't have anything to gain from a tiny runtime and I wanted more powerful tools for making a DSL in there. It worked out perfectly, I'd do it again.
Yeah, I'm not saying there aren't usecases that it would excel at (sounds like you found one!), I just haven't really had a problem that I thought it would yet. I've come really close though