I think Patrick Chase's argument about the engineering complexity is key: this is an expensive saw. That said, my impression from trying the saw in Amana is that this high priced tool actually offers significant unique function for the price. This is the only coping saw I've ever seen where you can accurately follow a curve with the tensioned blade and the spine swivels freely and completely independently of the direction of the cut. You could cut into a long edge, and then cut a tight spiral of many turns without any readjustment of the saw or pause in cutting. It feels very different from other coping saws.
Whether that is something you want to pay for is a separate question.
Incidentally, I don't think the light weight is needed in this saw because the weight is only relevant in twisting the spine rapidly back and forth as you cut complex curves. With this saw, the spine does not need to flop back and forth as you cut a complex curve. I don't see the weight making much difference to the sawing stroke itself, but I could be wrong.