I got excited when I saw the core was JS (as writing TypeScript/JS is something I enjoy) then I saw that all modules are written in python... That doesn't seem to make a lot of sense to me, allowing for any language or a subset of languages makes sense but writing the core and plugin system in different languages.
I was disappointed that this was implemented in JS and Python. If I decide to experiment with this, the first thing I'll do is port it to a (compiled) language that I prefer.