"Bitcoin is evil… so far almost all of the Bitcoin discussion has been positive economics—can this actually work? And I have to say that I’m still deeply unconvinced."

"Bitcoin is not a legitimate currency but simply a risky virtual commodity bet. . . . Bitcoin lacks the essential attributes that are needed to support a widely recognized transactional currency. If Bitcoin was allowed to proliferate as a currency it would produce greater economic uncertainty, reduced trade and lower individual standard of living."

"It's a bubble. You have to really stretch your imagination to infer what the intrinsic value of Bitcoin is. I haven't been able to do it."

"The developers of bitcoin are trying to show that money can be successfully privatized. They will fail, because money that is not issued by governments is always doomed to failure."

"And, in the greater scheme of things, bitcoin is small: even at a roughly 10 billion dollar market capitalization it is almost irrelevant in financial terms. This is probably roughly the peak market capitalization achieved by Beanie Babies in 1999. There are indeed important and valuable ideas that exist in bitcoin’s design. But bitcoin itself? I believe its volatility and built-in irreversibility will doom it to the ash-heap of history."

"The federal reserve comes out with their own version of the bitcoin, let’s call it the “USDcoin”, they make a .001 (or some other arbitrary number) USDc the equivalent of $1 and they make it very easy to use. You can have these deposited into your existing bank account and they are immediately converted to dollars and when you send dollars out of your account they are immediately converted to USDc. Then the government also implements anti-bitcoin laws that make using bitcoin difficult or impossible to use. Of course they will claim bitcoin was being used for illegal purposes and money laundering. This will be the end of bitcoin."

"To the extent using Bitcoin has any benefits now — convenience, cost-efficiency, putative anonymity — it’s because authorities haven’t been taking it very seriously. As officialdom becomes more assertive, Bitcoin will become more difficult and expensive to use, and less anonymous."

"But make no mistake, Bitcoin is not the currency of the future. It has no intrinsic value. . . . Bitcoin? Nada. There’s nothing keeping it being a thing. . . . Again, Bitcoin might go up a lot more before it ultimately ends. That’s the nature of bubbles. The dotcom bubble crashed a bunch of times on its way up. Then one day it ended. The same will happen with this."

"In theory, bitcoin could become a lawful virtual currency if the bitcoin community gave up anonymity and therefore incorporated the identities of bitcoin senders and receivers as part of the currency. But that would eliminate the cash-like feature that makes bitcoin attractive and vastly decrease the demand for bitcoin. That does not seem like a viable path forward. . . . While I praise the sheer ingenuity of bitcoin and its payments innovation, it should be buried."

"It's not anonymous, it's not free, it's not instant, and it's not convenient. It's extremely difficult to make money on it, mining is useless, and it's literally impossible that it will ever go into widespread use. Unless you have an ideological stake in the concept of Bitcoin (or want to buy drugs and/or child porn), there is literally no reason to get involved in it."

"All of which is to say that doing anything legally with bitcoins — and especially converting them into fiat currencies — is going to get harder and more expensive as governments involve themselves. So hard and so expensive, I’d argue, that any advantages the crypto-currency may have over normal means of exchange, like credit cards, will soon disappear."

"The problem, as I see it, is that bitcoin only value is it’s medium of exchange, without any real effort. It is ripe for fraud and manipulation, but what fiat monetary system isn’t. The automatic systems of growth to a finite number of units along with the division into smaller increments are intended to eliminate the problems of past monetary failures but cannot control human nature. As the medium of exchange and perceived value increases, hording will occur."

"Bitcoin’s path to the grave has always been fairly clear to me. . . . You can’t seize a Bitcoin like you can seize a dollar, since it’s simply an alphanumeric string. But people need to be able to get their money in and out of the Bitcoin economy in order for it to be a useful alternative. With Mt. Gox and other Bitcoin go-betweens having such a hard time staying afloat, it probably won’t be long before even some Bitcoin diehards consider packing it in."

"Ultimately, it’s greed – not a genuine interest in a fundamentally stronger alternative to the status quo – that’s driving Bitcoin prices. So forget Bitcoin being a contender as an alternative currency. At best, it’s a speculative investment."

"Everyone agrees that Bitcoin is an amazing proof of concept from a technical standpoint, and has succeeded in raising much awareness for the current flaws of the monetary system. But does Bitcoin really address these flaws? More and more prominent economists and net activists say no."

"So to recap: Bitcoin has swung from $265 to $60 in less than a week. Useless as a store of value, seriously broken as even a txn currency."

"Now here we are in a world of high information technology — and people think it’s smart, nay cutting-edge, to create a sort of virtual currency whose creation requires wasting real resources in a way Adam Smith considered foolish and outmoded in 1776."

"Well it has finally happened. We looked at those charts of ever rising price of bitcoin and said this cannot last, and it hasn’t. The bitcoin bubble has finally peaked and now all that is left is to watch its steady and inexorable decline. So what now for bitcoin? It will crash and disappear like Pets.com, Leheman Brothers, and Anglo Irish Bank, existing only in the memories of economists."

"Bitcoin is a Ponzi scheme—the Internet’s favorite currency will collapse."

"The very reasons why Bitcoin has taken off today will be major reasons why its value is likely to collapse tomorrow. . . . [dramatic price instability] will cause the ultimate failure of the Bitcoin experiment. . . . Bitcoin will fail because a small number of hoarders control most of the supply."