A rationalist who cannot find value in marginalizing errors in decision-making by some process has no grounds to accept that process as meaningful or valid. And

A rationalist who cannot find value in marginalizing errors in decision-making by some process has no grounds to accept that process as meaningful or valid. And dreaming up ideas about things you believe to be unknowable is exactly that. That this opens you up to a much wider world of ideas is not surprising. As soon as you abandon the constraints of fact, you are free to think about any number of fictions. However, these fictions don't provide you any real advantage, which is why they are called fictions to begin with.