Not attacking at all - just discussing.
All these appear to do is prevent the NVH from reaching the passenger compartment at the expense of rigidity. It doesn't prevent the NVH from occurring in the first place. All you'd be doing is isolating the effect to a different area of the chassis. Flex is flex, and allowing the chassis to flex more is going to work the metal harder. Maybe the amount is negligible in terms of practical life, but I rather doubt even that, as you'd see the OEM braces being removed from the cars if only for the benefit of a quieter cabin. Removing chassis braces (or allowing more chassis movement) will not result in a longer lasting chassis, nor will it make the suspension 'work better'; quite the opposite, in fact.