Source code is for humans, and thus should be written in whatever way makes it easiest to read, write, and understand for humans. If your language doesn't map onto ASCII, then Unicode support improves that goal. If your code is meant to directly implement some physics formula, then using the appropriate unicode characters might make it easier to read (and thus spot transcription errors, something I find far too often in physics simulations).
I'm a practitioner of neither though, so I can't condemn the practice wholeheartedly as an outsider, but it does make me groan.
Consider a simple programming example, in C blocks are delimited by `{}`, why not use `block_begin` and `block_end`? Because it's noisy, and it doesn't take much to internalize the meaning of braces.