In 1995, many experts confidently claimed that the internet was a fad.
This was not an isolated incident: since WW2 we have heard, time and again that "this new technology will never catch on."
More recently we have been told that Cryptocurrency is a scam.
So, is it (a scam)? Or have the authority figures failed to understand (or be honest about) network economics, and the powerful role it plays in creating value in an online world? This article is a great summary of how network economics do a good job of explaining the cryptocurrency phenomenon (and possible valuations for different cryptocurrencies based on that network effect).
The argument goes like this: as more and more people choose, freely, to use cryptocurrency as a means of exchange then that simple fact (if / when it happens) will create value, via the network effect. Similarly, it's arguable that network economics already explain how existing fiat currencies work, and that the value of a Swiss Franc or US dollar is not, in the final analysis, "conferred" by the governments that back those currencies but by everybody in those countries (and elsewhere) agreeing to go along with it. Whether participation in a national currency network comes about by coercion, voluntarily, or a bit of both, does not matter much for the value of the currency, what matters is that people agree to participate in the currency network.
At this point, it's far from certain that cryptocurrency will gain broad acceptance, and it's far from certain that people will use it for daily transactions, but if they ever do then the law of network economics says that there will be intrinsic value in that. Nor is this "all theory": there are precedents for this from other internet phenomena. Facebook produces no content but is worth billions due to the network effect. Airbnb has no properties that it owns or manages, but it's the largest provider of "hotel rooms" on the planet. The value of these companies lies mostly in the network effect.
So there is the potential for great value to be created, despite what Jamie Dimon and other talking heads are saying. Yes, it's true that no single currency has yet established itself as the default network for global exchange, and there is considerable risk that an investment in a specific cryptocurrency could go straight to 0. However none of this means that the overall concept of cryptocurrency is worthless, it just means we don't know which final form it will take (yet).
Of course, just because "the establishment" is only latterly coming up to speed on how cryptocurrency creates value, does not mean that they can't destroy it. Right now, I suspect that many with vested interests in preserving the status quo are hoping that cryptocurrency implodes / goes away on its own (with a little help from PR men and other experts talking it down). When that fails to happen to their satisfaction, there are increasing escalations that we might see, including attempts to destabilize it (make the bubble go "pop"), creating cryptocurrencies that traditional "gatekeeper" institutions control (on so-called "private" blockchains, and, defeating the point, in my opinion), and if that fails, they will try to regulate / legislate it to death. The reason for this is simple: part of the promise of cryptocurrency is as a means to provide secure digital, global transactions without needing banks or payment networks like Visa, who constantly step in to take their cut. The promise of cryptocurrency (as yet unrealized) means no more currency exchange scams, no more 2-3% charge for simply processing a transaction and maybe, just maybe, a reduced role for the bankers who seem to have more, not less, power since they almost destroyed the world economy in 2008.
Whatever happens, the network effect that's upended media, hotels, taxis and other areas of life is now poised to do the same thing with our money. I can't say whether or not it will be a net positive or not. In fact, it's not hard to imagine it having a hugely destabilizing effect, as it might destabilize the "dominant" global currencies, led by the mighty US Dollar. Either way, the growth of cryptocurrencies is happening now, and it's gaining momentum so quickly, and so globally, that it might be unstoppable.