In listening to Michael on a recent episode of "Boxmining" that featured Max Keiser, Keiser continued a familiar line that cryptocurrencies open the door to distributed wealth and a sort of "democracy in money" revolution now missing from the fiat mechanism run by central banks. The danger to cryptocurrencies seems to me to be the same as resides in fiat ones: an elite monopoly of the currency(ies) and subsequent oligarchic rule on a global basis. The Golden Rule appears to apply in cryptocurrencies as well as in fiat and traditional money (gold & silver): He who has the gold rules.
As far as I can determine as an amateur in cryptocurrencies, there is nothing that would stop an incredibly rich individual(s) from buying up all or at least a "lion's share" of - say - Bitcoin. While there are individuals with multi-billions of $US, there are corporations, hedge funds, etc. which control 100s of billions of dollars. Any one of these could easily arrange a large set of fully controlled proxy organizations to begin working to gradually gain control of all of the available Bitcoins. A similar program could exist for other cryptocurrencies in the top ten. In time the people who dominate fiat currencies could dominate all the "royals" of cryptocurrencies.
At the same time, the elites who control central banking could easily use their power over politics to "regulate" ICOs and exchanges. These elites are not nice people: they are people driven to rule the whole globe. In the USA they have fended off any audit of the essentially private Federal Reserve Banking System. ("No snooping, please!") Further, these elites, at least in part, have apparently stolen a vast portion of USA gold bullion. Elites aren't nice! They operate a global criminal syndicate, laundering money in their banks.
Who would actually know if the Federal Reserve decided to reset the US economy and the global nature of the $US (called "petrodollar") by cutting a check, so to speak, and buying control of all major cryptocurrencies. At the same time the Federal Reserve could, working with the Dept. of the Treasury, set up a national cryptocurrency, a national exchange, forbid private exchanges, and allow trade of "Fedcoin" and other top twenty cryptos, all of which it had already gained control. It would also have the power to churn cryptocurrency markets, while its experts vainly talk about "market forces," as an explanation. The IRS would certainly be unleashed upon the cryptocurrency world.
In the Western elite scheme of things the world will be divided into a small set of administrators whose chief task is to shape the lives of the masses in ways congenial to elitist designs.
Further, the central banking syndicate is global and most central banks are connected to Western ones. There is a vested interest in their controlling currency - whatever it may be. The Chinese central bank works with Basle, Switzerland's Bank for International Settlement ("BIS"), which in the West is considered the central bank for central banks. China will use its waxing power to leverage up its role, but it has a vested interest in participation. What Russia and Iran do, for example, may be to temporarily operate their central banks as associates of the Chinese central bank, until political normalcy can be restored to the globe. The point is that the central banks are unlikely to give up their power.
As long as cryptocurrencies are limited to set amounts of coins/tokens, they are vulnerable to being bought up by proxies of megalomaniacs. If the cryptocurrencies are open-ended in their creation - theoretically totaling in the trillions, or more, a central bank, able to add endless numbers of zeros at the end of the currencies they produce as fiat digital currency, will then become the only entity on Earth able to buy them all.
I saw today a video release on TenX by Julian Hosp. He clarified current matters that might be of concern to his enthusiastic followers. He spoke excitedly about the large number of interested banks, financial institutions, venders, investors, big shots in Silicon Valley, etc. My thought in listening to Julian Hosp was that he is over his head among these predators. He may view himself as a predator also and "welcome the competition." I see his organization as possibly becoming something great in the cryptocurrency world, which I believe will become at one with the real world of products and services. I also believe that it will be coopted by the great predators increasingly stopping by for lunch. One day, he will likely be the lunch, and his organization will then belong to others with greater fangs & claws. It is difficult to dance with the devil and not go to hell.
Naïve people may rebel against the predator-prey model of life on Earth, but its seems to hold through time. Can the mice "bell the cat?" I wouldn't bet on teenagers and millennials facing down the established predators at the top. These cryptocurrency cowboys are to the predacious elite like " flies to wanton boy; they kill them for their sport."