This is a good point, even without polymorphism there are risky refactors, but the polymorphism increases the number of potential risky refactors. On top of th

This is a good point, even without polymorphism there are risky refactors, but the polymorphism increases the number of potential risky refactors. On top of that, it might be a lot more obvious that turning a vector into a vector of vectors might be risky, but that you can iterate on Option won't be top-of-mind to everyone.