USD works as currency because it has a pretty stable and small rate of deflation, a property that the fed tries to maintain. It works to trade value and gives a

USD works as currency because it has a pretty stable and small rate of deflation, a property that the fed tries to maintain. It works to trade value and gives a subtle nudge to promote trading. Bitcoin had the mission statement of being a currency, which it has failed at. It's instead a highly volatile (and potentially highly profitable) investment. So someone could be right that Bitcoin would not succeed (at being a useful currency) and still have been wrong to not buy in (they should have gotten in when the getting was good for the very reason it would fail to be a currency). But it was and is more like gambling and less like "mattress money".