Oh, that great! My major point of friction with LaTeX is that using unicode is not straightforward. You sort of can, by including the right packages and using the right interpreters, but it imposes strange constraints involving the fonts that you can use and whatnot.
Regarding the usage, it's probably my fault. I tried to compile it locally and it didn't work at first (requires newer rustc version).
Possibly you are describing how it used to be before the input encoding standard for LaTeX switched to UTF-8?
Probably there is a magic combination of engines and packages that allows to do everything at the same time, but I haven't found it.
If this works natively in typst, it's a great selling point for me (although I dislike the markdown-like syntax).
I suspect as typst only has a single implementation (I believe), it won't have the problem of different engines ;)