This reminds me of Java applications that you can immediately tell are Java because of the weird font. I don't see an advantage over using native system fonts. As far as I know you don't need a license to use fonts installed on the system running the application. Why does the font need to be bundled? The wide spread adoption of this is going to make go programs stick out like a sore thumb.
As touched on in the article, you need a standardized font you have control over for automated testing, to make sure you're getting reproducible results. OS fonts are too inconsistent for that.
Now, why they couldn't use any of the literally hundreds of other open-source fonts instead that Google made…