[goerz]

If that’s what’s most appropriate for the field you’re working in, sure, why not?

Of course it will limit who will be able to interact with your project, which can be a good thing or a bad thing. For the math-unicode in numerical software, you may not even want someone without at least a minimal math background (enough to understand Greek letters and math symbols) working on the code. Likewise, a project that’s inherently Chinese, where it doesn’t make sense for the users/developers not to know Chinese, should feel absolutely free to use Chinese symbols in their source code.

On the other hand, if you do it gratuitously, you just unnecessarily limit collaboration. I’m ok with that, too, personally: it’s your own foot you’re shooting.

[goerz]

I also don't see Chinese symbols as fundamentally different from non-english ASCII. It's pretty common for Physics bachelor students to show still naming their variables and write comments in e.g. German (my teaching background). I'll push them to kick that habit pretty quickly and switch to English, but this is no different from them still writing the bachelor thesis in German and then switching to English for the master and PhD: there's nothing really wrong with it, but you won't have any reach within the scientific community if your work is not in English.

There's really nothing wrong with beginners starting out in their own language. Why shouldn't a 14 year old Chinese kid write their first programs using Chinese characters as identifiers? I'd much rather have a language support full Unicode they way Julia does than to force everyone into ASCII.