Prints to where? stderr? Fine for a simple CLI tool, but people might want to do something more complicated when an "unrecoverable" exception occurs.

Take for instance a web framework like Django that responds with a 500 error page with a stack trace when an exception occurs.

There are interesting problems to be solved in the space of error handling, e.g. error handling in asynchronous code. But Rust is not even matching the state of the art achieved by Lisp and Python decades ago.