Oh. XMR.ID is not an email service.
Names simply resolve to Monero destinations to simplify payments for the sender.
The two formats whatever@example.org
and whatever.example.org
were chosen by the designers of OpenAlias, the set of definitions XMR.ID builds upon.
The animations in the website's screenshots-section show XMR ID's in action.
Note that the email address requested at signup is used by the system to send further instructions.
Personally, when I opened the link yesterday, I wondered if I was looking at a product for 4-year olds: Big round shapes, bright colors, ... and nothing that would give me a clue about what I am actually looking at.
I might simply not be in it, but who's the target audience here?