Actually it has the best monetary policy: it's supply is inherently regulated and prescribed: https://en.bitcoin.it/wiki/Controlled_supply. Intellectual-yet-idiot Krugman is a Kardashian of the economic's world. Popular because he is popular, nothing more.
"Economists" should take a note from the medical profession: First do no harm. AKA unless there is a extraordinarily compelling motivation, the best course of action is no action. We have spent the last 100 years in a system where the very base layer of our economy, the currency, was cooped for social engineering. "Wouldn't we all be better off if we made the cost of lending almost 0?" -> Housing bubble. If Wizard's of Oz are constantly mutating the value of money and lending the only people who can prosper are the Wizards (politicians) and the Bankers. The last 50 years of economic prosperity make that evident.