What about rapid prototyping? Perhaps the biggest strength of the lighter, more dynamic languages is that they require much less work to play around with ideas in the early days. On the other hand, if you can’t then tidy up the code that sticks, to make it into something that is more systematic and maintainable over the long term, you’re either going to waste effort rewriting it or you’re going to take on ever-increasing levels of technical debt, and either way your progress will be slower.

Refactoring really, truly and absolutely has nothing to do with rapid prototyping, nor does rapid prototyping has any use for refactoring.

> you’re either going to waste effort rewriting it

Throwing one away isn't "wasted effort", it good practices: you created a turd the first time around and learned a lot, polishing that turd would be wasting time.