Design controls are essentially implemented to ensure traceability on their released product. The idea is that if the released product has a defect which interferes with its function and effects the consumer, all history of the product from design to manufacturing is traced, which could be found in a Design History File, in other words design control tries to ensure the highest quality to consumer. When processes/procedures are not properly implemented in a lab or by a technician/operator nor documented, could potentially result in a failed device. The FDA has very strict guidelines to ensure traceability of devices as well.

Chris