Yup, those new features had me thinking, too. In theory, the referral program sounds good, and maybe in 20 years I can get five writers and half of their fee rolling in. It's gonna be so worth it!
The email subscriber thing... personally I haven't figured out a scenario yet in which I want to sign up for anyone. I'm using Medium all the time, I read and bookmark everything I want to read, plus Medium sends tons of notifications. What's the point of receiving an email, too? Nonsense.