The only real selling point of any of these is “Not gmail.”

Like. Sure. If you email your friend from your $redacted e2ee military-grade encryption account, and your friend also has the same provider of their e2ee military-grade encrypted email account, then yes. They’re encrypted, and $redacted can’t really provide much if they get subpoenaed. If your friend is using gmail? Your emails are being read by gmail.

They often have other features, like I have a catch-all mailbox set up for my domain because I’d rather give lemmy$date@example.com than my actual email for various reasons. But their privacy ends where gmail begins.