The noise floor of economy cars is something you could possibly not notice until you actually experience a long highway trip in a luxury brand. That lower amount of road noise is a subtle but noticeable impact on fatigue.

Like a nice pair of expensive headphones, you don’t understannd difference until you experience it. Like a nice pair of headphones, it’s not a necessity, either.

That said, I don’t think that has a whole lot to do with weight. NVH reduction techniques like insulating material and structural adhesives are not a major weight consideration, it’s more of a cost issue.