No, you’re missing the difference. Gmail requests the embedded resources when you open the email. So it’s still possible to track open rates through it, even if

No, you’re missing the difference. Gmail requests the embedded resources when you open the email. So it’s still possible to track open rates through it, even if the proxy obscures your IP address. Apple Mail requests the embedded resources without you opening the email, so you cannot use it for tracking open rates. A lot of people assumed this is what Gmail did, but it wasn’t actually the case.