The discussion is pointless.
The internationally usable mail addresses should be ASCII.
You might think it better if your address could be represented with
non-ASCII Latin characters, which you can recognize without any
difficulty. The problem is that not all characters in the world
If my address is represented with Chinese characters, most of
the people in the world can only vaguely recognize the shape of
the characters. They can't recognize the important characteristic
of the characters. They can't remeber the shape. They can't reproduce
the shape. They can't know how the character is encoded. Even I don't
know how the encoding of my name is. The encoding is processed with
the input frontend system which is designed for those who knows Chinese
characters well. Most of the people in the world does not have such
a system, and even if they have, they don't have enough knowledge on
Chinese characters to use the system.
So, if you want to receive mails internationally, your address should
be composed of ASCII characters only.
Of course, in locally closed environment, people can have thier own
conventions. But, that is not the problem to be discussed here.