Knowledge work involves (1) a process of clarifying what is vague, and (2) a process of carrying it out. The latter — execution — is the easy part. Clarification is what gives you a headache. In knowledge work, being "stuck" means there's something vague. In other words, there's something that hasn't been clarified. And because you can't act on it, you're stuck.
To make your thinking clear, methods may come up that look inefficient from an execution standpoint.
Typing out the entire national anthem four times would be easy. Offer 5,000 won and you'd probably find plenty of takers. (Better than a delivery side gig!) But ask people to write a blog post of around 1,000 characters and the number of volunteers would plummet. Typing the whole anthem four times comes to about 1,200 characters. So why do people avoid blog writing more, even though it involves fewer keystrokes?
The reason is that blog writing is an unclear task. With typing out the anthem, what you have to do is perfectly clear. All that's left is the execution of typing. Blog writing, though, requires a great deal of turning the unclear into the clear — choosing a topic, constructing sentences, and so on.
That's why writing can't help but be good training for clarifying your thinking. Writing starts with every sentence and every word in an unclear state. You're converting something entirely unclear into something clear, so your clarification skills can't help but improve.