Believe it or not, there are senior engineers with comp packages of $300k+ who spend 80%+ of their time writing and being in meetings and very little if any actual coding. You could really call what they do as writing blog posts, just for the company.
Blogging about a topic is a good way to build network and raise awareness. A 10x developer surely strives to be a good blogger; writing is a key skill of such developer, and it needs to be continuously improved.
Technical writing is a great skill and a valuable one. I used to write blog posts, a lot. It truly improved my ability to write great documentations, and i'm getting appreciated a lot by that skill, well on the other hand, if you are talking about the "how to reverse a string in x?" types of content, it's completely understandable.