[simple-thoughts]

Most dollars are created by offshore banks and are not backed by deposits at the federal reserve. The federal reserve only indirectly affects the value of dollars through manipulating inflation expectations. If people think the fed is easing, they buy assets which pumps the collateral of offshore banks which then have larger balance sheet capacity to issue new dollars backed by that collateral.

So even if you are signing contracts in gold/oil pairs, effects of fed decisions can impact your trade in ways that you are protected from in usd/oil pairs as gold is usually viewed as a safety asset - so when animal spirits take off due to fed statements gold can go down while oil takes off. This has in fact happened several times over the last decades.