Is anyone familiar enough with Medium to know why someone would publish their blog on the platform, and lock users behind a paywall in order to read their blogp

Is anyone familiar enough with Medium to know why someone would publish their blog on the platform, and lock users behind a paywall in order to read their blogposts? Do they get a cut? I'm not even sure of price, but just see a screen that lets me know I've hit the end of my "Member Preview".