I feel the opposite - I don't understand why a modal should have a route most of the time. It seems clunky and usually should not be a part of browser history.

Login and Signup for instance so you can send a link to a friend so they don't have to find the buttons on their tiny phones.

Settings, so you can send it to your parents so they can fix that shitty notification spam they got going, etc.

That's just my take on it.