> With demurrage currencies, everything works like TIPS. Yields may be negative but they are free from inflation and deflation.
Not at all true of historical demurrage currencies, with are subject to inflation/deflation as normal but also have reduced nominal value over holding time.
ISTR the term has been resurrected for crypto products, but I can't find any details of how any crypto demurrage currencies work that would confirm or deny that they are somehow insulated from inflation/deflation and only change buying power by the demurrage charge, though I can't see it being likely to work in practice.
In theory, you could have what is basically a “stablecoin” managed against a price index like the CPI-U instead of an actual fiat currency and then add a demurrage charge on top of that (which could provide stabilization resources, so it's not completely irrelevant to function).