Even if you read code naturally, fishing out individual contributions from a Github page is a chore; there are lots of things people can do on Github that will make them appear at first glance to be productive and important.

Lots of applicants give us Github links, and while I'm very happy to have them (please include them), I still have to look at the list of projects and figure out "is this his project, or is it a project he just likes and follows; are these his commits, or is he just backporting someone else's patch" &c &c.

I can't imagine how a hiring manager dev who hasn't used Github before could be expected to make decisions from it.