Potatoes are not necessarily healthier. 2/3 cup of skin on boiled potatoes has 20 grams of carbs and only 2 grams of fiber and 2 grams of protein. If you peel the potatoes, you lose a lot of the fiber.
A whole wheat roll (2 1/2 inch diameter) has 18 grams of carbs and almost 3 grams of fiber, and 3 grams of protein.
Of course all those numbers change when you add butter or cheese or sour cream.