Ghost needs emails for a couple of reasons.

1. (Required) Ghost does not do user passwords. They use magtic links, which they send out via email when signing in. It’s just how they have chosen to do it. You can ask them why they don’t want to save passwords.

2. (Optional) Ghost has a newsletter function. If you enable it, you need to setup a bulk email service, like Mailgun. Even regular SMTP won’t really work there. It can send out a newsletter everytime a blog post is published, so the members will get notified.

I recently had to do this email dance with a Ghost instance setup, where most of the email ports are blocked on the network. I know how you feel. I also wanted to just use passwords, but not currently possible with Ghost.

Other services might do the same as Ghost. I do host many services, that does not require email setup though.