Several decades ago, when I worked at a company which made very high power industrial products, the part of the product which was the most challenging was the metal fabrication area.
Just look at one the enlarged images, to see the amount of sheet metal and metal bars that have to be cut, bent, formed into shape, welded, brazed, tapped or chamfered. Many times the individual components could weigh several kilograms and its surfaces had to be machined with high precision.
When all the parts were finished, they had to be anodized, painted, powder coated, plated or any other surface finish.
In some extreme cases, we would cast or extrude large components with outside contractors and finish them ourselves.
That this company can perform all of these operations, and provide you with a fully assembled module, is a significant value adder.