I think it depends on your end game. What are you trying to accomplish?

For example, I wrote this article to bring awareness to The Writing Cooperative. But it’s not an advertisement, per se, it literally serves our mission statement: helping each other write better.

It also depends on the size of the niche. I love writing and writing is a very large niche on Medium.

So I think you can go too broad or too narrow when targeting an audience.