> Proof of work has always had an economic flaw that you could theoretically temporarily rent enough mining power to perform double spends of more value than th

> Proof of work has always had an economic flaw that you could theoretically temporarily rent enough mining power to perform double spends of more value than the cost of renting those devices. It’s not a flaw if it’s only theoretical. In practice, no miner with billions of dollars of capital bound in mining hardware would rent it out to someone who might do something that would significantly depreciate this capital (e.g. attack the Bitcoin network).