Much insight and clearly written words in this paper, thank you for posting this and bringing this huge issue to consciousness of the many people who do not see why there would even be a problem
There was that joke about books , where they were described as a revolutionary tech that allows to store text and images, display it, index it with direct access , with complete anonymity, privacy , and zero power consumption…
We could have the same joke about a revolutionnary currency, that can be used for any transaction , with guaranteed zero down time, total anonymity, untrackable transaction history, bug free, zero day free, complete offline storage with unbreakable air gap protection, ddos immune, fine grain divisibility, zero power consumption, worldwide coverage with a vast alt-coins ecosystem in every country of the world, deep penetration, trust level and adoption even in remote and wild areas, reliable in emergency situations even when the network is down or unreachable, massively scalable, forkable, all this with thousands years experience of the widest user base ever, thousands years documentation and bibliography, a vibrant community to meet and talk with in every country all over the world , AND you can buy a beer right here today at the corner of YOUR street with it.
Now, someone create a competing currency with digital stuff and I will start to believe in a cashless society good luck pal
As for the OP question , I can imagine digital SafeCoins as a backing value for material , printed or metal safecoins. These would have some of the above mentionned benefits , that can not be achieved digitally today, I suppose ( bug free, air gap, no zero day, anonymous, zero power drain…)