The examples in the article are simplifications for the purpose of illustrating the points. We'd almost never use nesting to any element all the way back to the

The examples in the article are simplifications for the purpose of illustrating the points. We'd almost never use nesting to any element all the way back to the HTML or BODY laments. But when you have elements like SECTION, ARTICLE, LI, DIV, etc which can be nested infinitely in HTML judicious use of the child selector is a godsend. The examples in your gist would not benefit from additional use of child selectors, but I'll bet they'd appreciate it if the parent elements did :)