In the current system, including for paying taxes, you can right now be practically independant from fiat money value fluctuations.

You just have to have a bank account and minimal fiat money for the day, the trick is to log on internet each evening and use all or most of the positive balance to buy gold or whatever fund you want to keep the balance near zero. You need to buy something? Just sell your whatever fund and use the fiat money immeditely to make your purchase or pay your taxes.

So no issue here, the current system allows you the freedom not to depend on fiat money value at the cost of one click per day.

Of course if everyone does that, all the private banks of the world have to change their model since the government granted priviledge of creating money is of no use anymore since all customers accounts have zero balance...