The Judge didn't rule that Bitcoins were money, but that they had value:
Finally, with respect to Count Four, the defendant alleges that he cannot have engaged in money laundering because all transactions occurred through the use of Bitcoin and thus there was therefore no legally cognizable "financial transaction." The court disagrees. Bitcoins carry value - that is their purpose and function - and act as a medium of exchange. Bitcoins may be exchanged for legal tender, be it U.S. dollars, Euros of some other currency. Accordingly, this argument fails.