It doesn't matter what the European Central Bank's stance on Bitcoin is. There aren't enough big exchanges in Europe to make any difference. There's only Bitstamp, and that's a shadow of its former self since the hack. The biggest USD exchange is still Bitfinex, and that doesn't care about the EU.
kraken? plenty of people use that too. plus bitcoin.de. plus bitonic. plus localbitcoins which is already gone in Germany because of regulations.
bitfinex seems very willing to bow to American state level legislation. if something European comes in then expect them to do the same.