“It’s best to check this box (above) and self-publish your work first, even if you plan to submit your article to a publication. It’s the only way your readers gain access to that box, which tells Medium to email your story to all your fans.”

I’m not sure what you mean. Maybe I misunderstand. Readers don’t have access to that box, you do. When I am about to publish something, it comes up checked by default. I have to uncheck it if I don’t want to send out email alerting my (three — sigh!) subscribers to the existence of the article.

What does this have to do with the part I highlighted?

I am a publication editor (MuddyUm) and I recently subscribed to emails from one of our writers. The last time I published one of their pieces, I instantly received the notification email. It was in draft when I published it. So you don’t have to publish it yourself first.

Why does this matter?

At MuddyUm we are OK with publishing work that is already published by the author. However, when published, these articles are buried in our feed. Because our feed, like any publication feed I am aware of, is chronological, they don’t get their moment in the sun at the top of the MuddyUm feed. Even if you publish and immediately submit the lag time, especially on a busy publication like MuddyUm, will cause your article to be buried beneath others.