Yeah that’s right. For a whopping one time purchase of 250$, you get a lifetime license for a @linux.com domain as an email alias/forwarding only. You cannot send emails from this. You can contact support to check if the alias you want is available too.
Imagine this on your CV. It is the ultimate flex.
There’s actually several things preventing you from doing this now. DKIM, SPF, and a couple others that I can’t remember.
There are situations they don’t cover, e.g. if you choose a sender address from the same domain as the real address. Obviously, lots of email services check for that, but it’s not universal - it was a great tool for pranks at university for me.