I agree there's no straightforward way to prove greater stiffness, at least at the consumer's level of technology. I'm also not clear on whether stiffness matters to a rider or is perceptible. But assuming cold-forged cranksets are stronger, you can get the same strength, if not stiffness, with the same or lesser amount of material. The sales metric, as with frames, is less mass with equal durability. So if the weight of this chainset is more like that of a Rene Herse than another double capable of 46/30 which is not cold-forged (I can't think of one at the moment), there's a tangible difference. Real nice looking design, though!