So number of daily/weekly downloads on PyPI/npm/etc?
All these things are a proxy for popularity and that is a valuable metric. I have seen projects with amazing code quality but if they are not maintained eventually they stop working due to updates to dependencies, external APIs, runtime environment, etc. And I have see projects with meh code quality but so popular that every quirk and weird issue had a known workaround. Take ffmpeg for example: its code is.. arcane. But would you choose a random video transcoder written in JavaScript just due to the beautiful code that was last updated in 2012?