The petrodollar is more important for US global domination than either arms exports or Hollywood culture, because it allows the US to be the biggest exporter of the dollar bills the rest of the world needs to be able to buy oil.
Most American have little or no understanding of this opening sentence. The US-led Empire's attempts at global domination means the threat of economic and military violence on countries who fail to support the Empire's interests of profit and power. Since the Vietnam War nearly bankrupted the US Treasury, the latter began in earnest to issue US Treasury securities backed by oil from Saudi Arabia and associates (which can only be purchased with US dollars) to capitalists and governments worldwide to support their increasing deficits. That is why our ruling class loves these head-chopping, medieval monarchs. 
US Treasury securities has long been regarded as one of the safest investments because they are backed by the economic and military power of the US. This means that those countries which do not support US policies, like Iraq, Iran, Libya, Syria, North Korea, Russia, etc. are threatened with, and often suffer from, both forms of power. With US government debt reaching $20 trillion dollars, many countries and capitalists are beginning to wonder about the safety of these investments, and many countries as reported in this article are starting to use alternative currencies to buy what they need. And, that is why the US is currently engaged surreptitiously and
overtly in so many countries to insure US dominance. This, of course,
costs money. As you can see, the deeper in debt the ruling class's
government becomes, the more they use economic and military weapons
against other countries. To me, this looks like a death spiral.Meanwhile most Americans are either fast asleep or their attention is totally focused on entertainment to be bothered with such events.