Three days ago, the Polish Financial Supervision Authority and the Polish National Bank issued a statement about crypto currencies (http://www.nbp.pl/homen.aspx?f=/en/aktualnosci/2017/ww-en.html).
I though it would include some new interesting arguments. But after reviewing the document, there was nothing new (in Latin nihil novi). Only the sort of information that is already known.
However, you have to give credit to the financial market supervision institutions, they are consequent when it comes to bad mouthing of crypto currencies.