Because Gold retains its value.
Its because people believe in it.
Would you say gold is important?
Why did people choose gold as the ultimate form of wealth?
Who made them choose gold?
Were they forced by governments?
Or did it come about naturally?
Is there something about gold that made it hold it's value over thousands of years of human civilisation, during which everything else has lost value due to entropic degradation?
It must be due to golds unique physical and chemical properties.
"Gold still represents the ultimate form of payment in the world. Fiat money, in extremis, is accepted by nobody. Gold is always accepted." Alan Greenspan