Taking a part that was assembled from several components and reducing it to one 3D-printed part has obvious benefits like weight reduction. But there are also other value propositions that start from the beginning of the design phase and reach towards end-use safety and reliability.
Take an example air duct. The original, conventionally manufactured design consisted of 16 individual components—the external enclosure, an internal baffle as well as screws and washers. Now, take that part and redesign for manufacturing with a 3D printer: One part, one component. Or, on the other end of the complexity scale, take an example of a turbine blade assembly that was reduced from 300 components to a single part.