Nintendo sells at their "recommended retail price", as is the case with many manufacturers. This price tends to be set at a higher margin to boost third-party sales. If this margin were already tightly calculated in Nintendo's own shop, there would hardly be any incentive for third-party sellers like Digitec to offer the product at all. However, the fact that shops like Digitec offer it has the advantage for Nintendo that their products can be seen and are present in as many shops as possible.