> I don't understand. You don't control any Mx records.

Yes, you do (on your own domain).

> You have an account with some company. You might lose it just like you might lose your Gmail account.

Yes, but if you use your own domain, the same account username can exist on another provider. I can still write you an email to "firstname[at]firstnamelastname.com" and reach you.

As for the email messages, if you do email correctly (by downloading emails to a local email client, and then creating backups, or at the very least, using Google Takeout to export your mailbox regularly), you don't have to lose your email messages.

> Also... You can use Gmail with your own domain. I don't get the meme with mx records.

Exactly my point. By then, you use Google Workspace, which is an email provider to your own domain.

If you wanted to switch to Microsoft 365, or Fastmail like I do, I am the sovereign of my email address. Nobody noticed I switched email providers when I changed from Google Workspace to Fastmail, and that's the point.

To be able to dump the provider when you need to. Sovereignty.

> Also... You can use Gmail with your own domain. I don't get the meme with mx records.

Additional reply to this: To use that, you need to fiddle with MX records.