It is important to realize that when you use a modern web browser, the address bar they tend to feature at the top of their main windows are not using URLs or even URIs. They are in fact mostly using IRIs, which is a superset of URIs to allow internationalization like non-Latin symbols and more, but it usually goes beyond that, too, as they tend to, for example, handle spaces and do magic things on percent encoding in ways none of these mentioned specifications say a client should do.
The address bar is quite simply an interface for humans to enter and see URI-like strings.
Sometimes the differences between what you see in a browser's address bar and what you can pass in to curl is significant.