Github track records aren't just about the fact of seeing your code; it's about the fact that you're proving you can work with the OSS community projects. That's a skill set in and of itself, as demonstrated by the recent extremely public bickering between gnome and canonical, for example. If you have a demonstrated track record of navigating OSS project drama like that and still getting your patches pulled into trunk, a company that wants to build a relationship with an OSS project is vastly more likely to hire you.
Re-reading your comment on preview, it sounds like you're looking at this like "Okay, I've coded all day on closed-source, now I need to go do up some erlang on some personal bullshit project and commit it to github, with unit tests and a meaningful commit, just so I have a track record to point to in a year or more when I'm looking for a job."
And I'm not saying that wouldn't work, but more that that's not the point at all, and any company hiring based on that is exactly as clueless (albeit a bit more up to date) as the company hiring based on a minimum of CCIE + RHCSA when looking for developers.