1. As a hiring manager that can code, I'd always open your GitHub if you put it prominently in your application.

2. If there was a lot of work on your GitHub or a really interesting project, I'd riffle through it.

3. If you had a bunch of good public code, that was a good signal, and you'd likely get an interview.

If you didn't put a GitHub profile, no problem. If you put one that was blank, then you at least lost some time from my review of your application having me click through, so it probably hurt you at least a minor amount.