Governments link the value of their currency, no longer to gold,...but to the value of their gross domestic product. So, therefore, national currencies have been cryptocurrencies, for decades. But then comes Bitcoin, and the others. These latest cryptocurrencies base their value on gross domestic perception. In other words, as long we can actually exchange some kind of goods or services with them, they will have value. Perception is reality. This is why national currencies are fearful.