(1) There are a surprising amount of Medium paying members. They may miss your article on Medium, but see it on social media.

(2) While non paying readers may not directly contribute to your earnings, their views/engagement boosts your article’s visibility internally in Medium’s recommendation algorithm, which in turn increases your reach to paying members.

(3) When Medium calculates your story’s earnings, they also include reading time from non-members if they become members within 30 days of reading your story.