Maybe one day human would also have a way to create gold out of water and air (they are all electrons and neutrons/protons anyway). From this point of view, a man-made limitation that is followed by all the participants can provide much better security than a nature limitation which might be broken by technology advancement
Do you really think that when it becomes possible to create gold out of water and thin air as cheap as dirt, gold will lose its appeal and shine? Regarding man imposed limits, they will stand only so long as all the participants are
forced to follow them. Up till now laws of nature seem to have worked much better and more reliable, lol...
John Law would undoubtedly and unreservedly agree with me