[Sir_Substance]

>This will ideally lead to the currency having a stable value.

That's not guaranteed. If I can't spend it on anything, it's monopoly money: regularly printed, but not actually currency.

Monopoly money is a stable state item, too. We've no reason, barring outside influence, to believe that anyone will ever start accepting monopoly money as a currency. The first person that did would be taking tremendous risk; there's an awful lot of monopoly money sitting in peoples cupboards. If they break ranks and no one follows, they'll be left with piles of worthless paper.

If too many of your coins enter circulation before someone starts accepting them as a currency, you could be left in the awkward situation where in order for a merchant to mitigate the risk of accepting your coins, they have to set the price of a loaf of bread so high that no single user of your service actually has enough coins to purchase a loaf.