[dragonwriter]

Taxes are an issue, but the other big things are:

(1) A tender of payment of a debt in legal tender currency, with some caveats and provisos, fulfills the obligation under the debt whether or not the person to whom the debt is owned wants to accept the currency, which has an effect if that person later tries to enforce the debt through the courts.

(2) If a US court awards damages, even if the injury consisted of deprivation of some other currency than the legal tender currency, it is going to award them in dollars. If the currency you actually hold is something else, you'll have to trade it for dollars to satisfy the debt thus created, unless the other party is willing to enter into an agreement to accept the other currency as a substitute.