Krugman was saying Bitcoin could NEVER work as a monetary system because it's designed to be deflationary. I.e. People would hoard instead of spend
This is why gold never worked as a monetary system either

Great insight !
. . .
It inflates initially; however, that inflation decreases to nothing over time (and, in fact, becomes deflation as the rate whereat coins are lost or made unspendable overtakes their production).
Yes, exactly like gold.
My comment was ironic, because gold was the universal money for about 5000 years, until it was taken over by fiat, which was initially a gold scam.
This is wrong. You Need to read Graebers History of Money
In modern times gold was reserve money and mainly used for international trade but inside the nation, money was largely credit money. Credit money and metal money have always coexisted. Gold itself wasn't the money it's the coins with stamp of the king on it. In essence money has always been a creature of law whenever there is a state