Maybe so, but they can confiscate those assets if someone "convinces" them that these are not legally tenable assets. If your Cryptocurrency hodlings are interpreted as "trespassing" on economic sovereignty, then the European governments will need necessarily intervene, if only for the sake of preservation of their own sovereignty.

Remember, nothing in life is certain, except for death and taxes; and the Government, whether that be Vietnamese, or European, or even Canadian, Maltese, Singaporean, or American, has the power to deliver both: at your doorstep, or at your footstep.

So, yes, invariably, ALL Governments are really scary institutions. All the talk of democracy, liberty, etc is the camouflage to mask that primal core of bestiality.