Firstly, even if this happened, there wouldn't be much of a difference for the crypto market. It's just one stable powerful fiat being replaced by another one. Secondly, I don't think this is going to happen. I believe that fiat will soon crash and be abandoned for something else, like cryptocurrencies. Europe is not living through its best times. Right-wing populists are EU-sceptics, trying to ruin it from within. Moreover, it seems that Europe is short on money since they decided to opt for Russian fees over justice just recently in PACE. The world's economy is barely holding it, IMO, and no matter how bad things seem with the US, I believe that the things in the EU are worse.