The main reason why Design controls are useful is because they test the quality, liability of the product. This would make sure that the clients do no get affected in a bad way by it. On the same way, it would prevent a lot of demands against the company that produced it. For example: Imagine that a patient gets an ulna replacement of titanium, most of the properties have passed the regulations required by the FDA but the elastic modulus of Titanium does not match with the bone and therefore it causes a lot of harm to the patient and it lowers the credibility of the company that made it. Design controls would make sure that all these details are solved.