> What if I want people to read me without needing a subscription or email disclosure?

Medium is where you can post and get a bit of what substack offers while giving you the ability to make your post freely available via the web.

> What's the email for anyway? So that you can get sent notifications of new posts?

On substack, you get the whole newsletter in the email. you dont need to go to a website. I use https://kill-the-newsletter.com/ to put them in my rss though.