Lua is fantastic for the config-as-code use case. Easy to read and write, with a lightweight embeddable interpreter, and it has almost universal library support across different languages/environments.
It's a shame that helm v3 didn't move forward with the lua engine[0]. I don't imagine ~=/1-based arrays were a worse timeline... And here we are 5 years later.
[0] https://github.com/helm/helm/issues/5084