Refactoring for no reason is not useful. But what happens in practice is you have a new requirement and you realize your hacked together “battle tested” system

Refactoring for no reason is not useful. But what happens in practice is you have a new requirement and you realize your hacked together “battle tested” system can’t possibly support it without breaking everything. So then you need to refactor first. And if you are actively developing then refactoring along the way is generally better than if you wait until the very end.