Well, the black list should have had some serious implications in terms of trade and financial service/transfers, but what exactly... I do not know...
Maybe it was just written up to scare some of those money laundering / tax evading / too competitive (by whatever means) finance centre sheltering / corrupt
pirate (or was it native American?) states... as mentioned by some German politicians
Never read into the details, the tit-for-tat interviews by those well paid politicians of the countries involved was far too interesting to follow instead of actually getting behind the story. Maybe that was the plan all along?