I personally find Medium’s passwordless authentication with email *really* unhelpful, because email doesn’t always arrive instantly (in my case this is something arcane to do with Google penalizing my ISP for forwarding too much email from personal domains to a GMail accounts) — and since there’s a time-out on Medium’s passwordless authentication, my login was failing. Every. Single. Time.
I prefer not to use other services (e.g. Facebook, Google, Twitter) for cross-service authentication because, I dunno, it just seems like a bad idea to give too much control to any one service provider like that.