Bitcoin is money, and money is always used for legal or illegal purposes. Cash, credit cards and the banking system currently extend beyond Bitcoin in terms of use for criminal activity. Bitcoin can bring significant innovations in the payment system and the benefits of such innovations are often considered far beyond the potential for Bitcoin shortages. Maybe this is what makes Bitcoin not banned even though it has not been declared legal.
It won't be legal until a big and influence country make an announcement to legalize bitcoin as a new currency that safe for any payments (online or offline). They can't do that because it's too complex to be a real currency.
Yeah, just enjoy it for now.