It's syntactic sugar, but the readability is worth it
[1]: https://en.wikipedia.org/wiki/Continuation-passing_style
EDIT: I believe prior art is Koka's with statement: https://koka-lang.github.io/koka/doc/book.html#sec-with
One level of callback nesting in a function is totally fine, two is a bit confusing, but if you have many async things going on do you really want 10, 15, 20 levels of nesting? What to do about loops?
I certainly greatly prefer async programming with async/await languages that keep the appearance of linear function execution to stacking my callbacks and having a ton of nesting everywhere
Since it's a callback, I assume it's up to the function whether to call it, when to call it, and how many times to call it, so this can implement control statements.
I would guess that it also allows it to be async (when the callback isn't called until after an I/O operation).
1: https://livescript.net/#:~:text=Backcalls%20are%20very%20use...
Is the `use` statement blocking (in which case it doesn't seem that useful)? Or does it return immediately and then await at the point of use of the value it binds?