For me, having some open source on GitHub, bitbucket and launchpad, has been useful in few job interviews because it kind of helped to avoid the "coding exercis

For me, having some open source on GitHub, bitbucket and launchpad, has been useful in few job interviews because it kind of helped to avoid the "coding exercise" and it was a good data point to prove I know how to use git and good development practices. But that wasn't the main driver for me working on open source. I think it is a nice side effect, but it shouldn't be a requirement; and definitely GH is not your CV (specially when there's so much open source not in GH!). That said, when I've been in a position that I could influence the hiring policy, I gave value to open source contributions because it did align with the ethos of the company. I guess it may not be important depending on who's hiring, but it is always useful if it is there and what you see is good stuff.