[AnimalMuppet]

Well... it might help, sometimes.

I think about something like Stokes' theorem: The integral of a function over the boundary of a manifold is equal to the integral of the derivative of the function over the interior of the manifold. But in practice, one integral or the other is often easier to do; that means that the theorem has the practical effect of letting you transform some hard problems into equivalent but easier problems.

But note well that I said "some problems". There are many problems that this won't help with. There are others where the problem you're trying to solve is the easier one, and applying the theorem turns it into a harder problem.

I suspect (but do not know) that the Yoneda Lemma is similar. It can sometimes give you a simpler way of looking at a problem. But just sometimes. Sometimes the Haskell/ML view is the easiest way to solve the problem you have. And sometimes it's not.