My observations of how 3D printing is evolving doesn't align with OPs. Why go to great lengths to print pressure bearing parts while many of them can be crafted

My observations of how 3D printing is evolving doesn't align with OPs. Why go to great lengths to print pressure bearing parts while many of them can be crafted from off the shelf parts from your local Home Depot? Stock steel, a welder, and some airsoft parts can all be used as functional substitutes and a lot of creators have functional models from these methods. In most parts of the United States a barrel (or anything other than the frame/receiver for that matter) is not a regulated part. You can order it online and have it show up at your door without ID or signing for it. Even in areas where barrels are regulated it only requires a few materials to electrochemically machine a barrel.