This is a weird thing to write about in 2025. AMP emails didn't really take off / get any kind of adoption did they. And HTML emails, annoying and problematic as they are have come a long way from the mess of client support and complete hack-job coding to where they are now thanks to standards and largely the popularity of web-based clients and the benefits those bring for email reading. GIFs inside emails unthinkable and ridiculous ten years ago. Today, not a big deal really for a good chuck of audiences. Etc.

On the contrary. The only place you get a standards-based email is Apple Mail on Mac and iOS. Gmail's web client is absolutely terrible for web standards. Outlook, on the web or app, is almost as bad.

I do remember using WorkMarket a long time ago and experiencing the bizarreness of their emails as they were one of the very few AMP users.

They'd send out emails about work opportunities and leveraged AMP to be able to go back into the email and tell you if it's still available to apply for or not in realtime, so you wouldn't have to click through and be disappointed it was already taken.