It's not arbitrary; gold (unlike copper) has been money for 5000 years.
And unlike copper, the United State's dollar was backed by gold for a majority of the 20th century while most other currencies were pegged to the dollar.
And finally, unlike copper, there’s $8-$10 trillion dollars worth of gold being used as a store of value globally.
Bitcoin has all of the core attributes of gold with the addition of being digital and having a fixed supply.
And unlike copper, the United State's dollar was backed by gold for a majority of the 20th century while most other currencies were pegged to the dollar.
And finally, unlike copper, there’s $8-$10 trillion dollars worth of gold being used as a store of value globally.
Bitcoin has all of the core attributes of gold with the addition of being digital and having a fixed supply.
It only makes sense to compare bitcoin to gold.