What does useFormStatus return, why must it be called in a child of a form element, and how does it eliminate prop-drilling for submit button state?

Imagine you're playing a game where you press a button to send a spaceship to the moon. The button needs to know if the spaceship is flying or waiting. useFormStatus is like a special walkie-talkie that the button uses to listen to the form's status, so it can show 'Launching...' or 'Launch' without needing a long wire from the form to the button.