> There are many ways to do so: race others in ranked online challenges, try to solve hard programming riddles, or study new paradigms. However, most programmers, whose work involves a form of writing, overlook writing itself.

The point is that sometimes that "doing" doesn't advance you, as it's not challenging anymore. Writing can be a form of deliberate effort to improve in your craft. There are many other ways to improve, the post focuses on one.