&gt; If you&#x27;re concerned about energy use and willing to trust a third party to verify the transactions, then why not use VISA?<p>Well, that&#x27;s my question.. They are already willing to trust the party that generated the code that they had legal access to their computer for this purpose. I think we would all be better off if they just required proof of monetary donation to some charity or something.<p>All that was accomplished here was shifting of trust on these individuals at some energy expense; it&#x27;s insane.<p>It&#x27;s nice theoretical exercise for sure, but I sincerely hope that anyone attempting to build yet another monetary system on waste of energy will seriously reconsider the idea.