The article is about optimizing the delivery of the CSS content, not about making it clear or concise or anything else. So, the point of the example then is to

The article is about optimizing the delivery of the CSS content, not about making it clear or concise or anything else. So, the point of the example then is to optimize for the content that is delivered directly on the page. Note that the only style used in the page is '.blue' which is the only style left in the header (they additionally specify that you should do this for content above the fold). The javascript will fetch the rest of the style after the page has finished loading. By loading only the immediately rendered styles, the entire page content finishes loading then the remaining styles are loaded. This is opposed to loading all of the styles, followed by the page content. Of course, when we're talking about a page that is around 1k in size either way it's not particular important.