Be conservative in what you do, be liberal in what you accept from others
If you attempt to redefine the term 'email' to be something broader, then you will inevitably be breaking and/or confusing users who expect the current implementation.
The current meaning of the word is simple and useful. Given someone's e-mail address, I can be reasonably sure of a way to send a text that will be received.
A world where 'e-mail' means a family of incompatible (by necessity, if we're enforcing secure communications) implementations would be worse than today.