One of the big benefits, indirectly already mentioned, is inflationary controls. Imagine the USD becomes worth less due to an influx of USD into the economy through some economic decision or another. The nice thing about this is that that means it requires more USD to purchase oil. And so countries and end up spending a greater percent of their reserves for the same amount of oil, and also end up taking on even greater amounts of USD to maintain balance.

Currency inflates due to inflated supply -> foreign countries take more of the currency out of supply -> inflation decreases. And it doesn't end there. The additional revenues from the oil producing nations are then invested into US securities and taken completely out of circulation. The vast majority of money is not brought into circulation through printing, but leaving the specifics of creation aside, this -in part- helps buffer any harm caused by the excessive 'printing' of money.

Thanks. Quite interesting. Wish I knew more about macroeconomics.