It is not a shortcut because it can't be implemented without knowing the `Arguments` internals. `format_args!("{}", "boo").as_str()` returns None for example.
It’s a shortcut in the sense that most, if not all optimisations are shortcuts. This one allows you to shortcut the usual formatting machinery if the result of formatting is a static string.
Like all shortcuts, it’s not something you can always rely on.
Interesting viewpoint: I see this as a distinction without a difference. I’m interested to know why you see it differently? What is its use, if not as a shortcut?
