There are no monetary standards anymore. Nixon abandoned the Gold Standard for foreign central banks in 1971, and for U.S. residents convertibility was ended decades earlier even.

Now you as an individual are perfectly able today to say that for every $100 you allocate for investment, $50 goes into buying gold (at ~spot price) and $50 goes into buying bitcoin (at ~spot price), ... or something like that. But the days of a government saying "our currency can be converted into and out of this bitcoin + gold basket, at this fixed rate of exchange", ... those days are long gone.