I think I understand now why people dislike continuation passing style for side effects. The continuations passed to the action can be called in any pattern, there's no inherent guarantee that an error handler cannot be called just because the corresponding success handler had already been called. In this regard they act like jump points in assembly more than functions in an equation.

I don't think this is such a massive problem. The entire imperative world is built on such things. I definitely think though that this model does not mix with autocurry.