[fqmwiugx] Email address

Typing an email address, for whatever reason, is awkward, requiring an interface with lots of buttons, or some other awkwardness like T9 input (with symbols).  Onscreen keyboards and handwriting recognition (by human or by machine) are similarly awkward.

Instead of typing it in, let an interface be able to accept it by scanning a QR code or reading NFC.  This of course requires the user to carry a physical token.  Maybe tattoo.  Cameras are more compact than keyboards.

The at sign @ annoyingly is not one of the 45 special alphanumeric characters that QR encodes efficiently, though it is not that big of a deal to encode 1 character with a byte encoding.  Perhaps modify email clients (or more ambitiously, the email standard, or even more ambitiously, create a new standard entirely) that permits one of the 9 other punctuation marks as a separator.  I advocate Space.

A physical token can deliver more data than a human can easily memorize, so can also usefully provide things like a public key or public key fingerprint.