By utilizing AMP for emails, Google wants to enable you to do more with emails, including things like RSVPing for events and managing your calendar, all without ever actually leaving your inbox.
On July 2nd this feature comes to everyone using Gmail on the web, with mobile coming down the line. These AMP emails will allow users to do the aforementioned RSVPing, but you can also fill out forms, browse images, edit things in Google Docs, and much more, all thanks to those fast loading, accelerated web pages using Google’s own custom webpage protocol.
There are some catches to this, besides only being available on the web at first. Partners do have to be cleared to send AMP emails, so not everyone will be able to take advantage of this. Google has to do a privacy and security check first, and then those sites and partners can use the new features. That’s good and bad, but don’t expect your inbox to fill up with these new emails in the next month.