No doubt 'activity' is a worthless metric. But someone who created and maintained a good repo, that's actually used by other people (doesn't have to be many),

No doubt 'activity' is a worthless metric. But someone who created and maintained a good repo, that's actually used by other people (doesn't have to be many), where the code is relatively clean and actually works ... this says quite a lot actually. Of course the major caveat is that this doesn't mean that someone who does not have this is 'not good'. Finally, if someone has made any number of contributions and they are objectively 'not good' - this is also a negative signal. So 'if there is a github profile' and the code/usage can actually be looked at, it might be useful criteria it just needs to be contextualized.