Gold as a substitute for iron has not been a satisfactory solution~!
Forming the iron ingot into the shape of a bull created value above and beyond the value of the iron. It would be worth some measure of gold today (much as in the case of the bull sculpture on wall Street (which is actually probably bronze)) as well, unlike 2-1/2 or 3 little slips of paper with a couple of extra zeros printed on them equaling the value of an ounce of gold. Actually that was a few years ago. Today it would take about 4-1/4 of these slips of paper to purchase the same amount of gold, or European goods, not to mention Australian, New Zealand or even Canadian goods, of just a few years ago. Look at the M3 chart. Iron takes energy and labor to sever. They don't even have to print the phony money any more, they can do it through the convenience of electronic entries.
Christopher Mayer, writing for the Ludwig von Mises Institute, stated it well: "Faith that paper money itself was of any lasting value would have struck our forebears as patently absurd."
"Whenever destroyers appear among men, they start by destroying money, for money is men's protection and the base of a moral existence. Destroyers seize gold and leave to its owners a counterfeit pile of paper. This kills all objective standards and delivers men into the arbitrary power of an arbitrary setter of values. Gold was an objective value, an equivalent of wealth produced. Paper is a mortgage on wealth that does not exist, backed by a gun aimed at those who are expected to produce it. Paper is a check drawn by legal looters upon an account which is not theirs: upon the virtue of the victims. Watch for the day when it bounces, marked, 'Account overdrawn.'" - Ayn Rand - Atlas Shrugged