but what if you earn money in that currency and never exchange it for any other currency just use it for life. the government would literately have to audit your savings account and proclaim that you owe X because your savings went up in value (and im not talking about interest paid by bank, i'm talking about just buying power of underlying currency).
that is no different than owning a gold necklace and government taxing you on it because gold went up in price. I don't think this is happening right now