Isn't a new thing, is it? There have always been new ways to test/differentiate candidates, but soon candidates identify the advantage and prepare for the test instead of actually becoming better at what they do. The scores of "Interview questions" books and websites are the evidence of this.

This is perhaps just the next thing, setup a blog and a bunch of repos on github, and if that makes the recruiter think you a better candidate, I am sure shortly everyone will do it, if they aren't already.