I strongly agree. It makes it much easier for a language to compete with incumbent languages if it already has basic developer tools like a test suite, a build system, etc. it also has the benefit of centralizing in standardizing the developer experience, compared to some languages where it's difficult for a beginner because there is no obvious correct way to do things.

I agree about formatting too, although every once in a while I do wish I could protect a specific section from automated formatting. Custom format and can be nice for things like mappings/tables, and certain deeply-nested JSON-like structures such as MongoDB queries.