The only reason I can think of for posting to Medium is revenue sharing, and I am not interested in pursuing a career as a creator at this time. Putting up content people MIGHT find via SEO tactics, only to have people driven away via a pay wall, seems self defeating.
I suppose you can always post to Medium you and somewhere else, unless that is a violation of Medium's terms of service. Then your basically turning yourself into someone who spams everywhere, not just Medium.
So I guess Medium is for creators and spammers. Am I missing something?