As someone making hiring decisions, I very much do visit the github accounts of my applicants. I consider the quality of their code and look favorably on them for making code available. I look even more favorably on those who bother to make licensing decisions for their code. Do you get an extra $5k for pushing 1k lines of GNU-licensed code? No. Did you get a callback on your job application? You bet. Do I take pride in the OSS work of my people? Yes. Does that factor into their performance review? Yes. Does that factor into their annual raise and prospects for promotion? Yes.

I have also hired people who don't have GitHub accounts. In those cases, they have some other proof of work. Papers, thesis, references (which are a drag, because then I have to also figure out how to vet the reference) and, particularly valuable, referrals from people I already know personally. This last one goes both ways: not only do I have high confidence in the good intentions of the person making the referral, I can then retrospectively assess this contact's ability to assess.