To the best of my knowledge, Bitcoin has not been made illegal by legislation in most jurisdictions. However, some jurisdictions (such as Argentina and Russia) severely restrict or ban foreign currencies. Other jurisdictions (such as Thailand) may limit the licensing of certain entities such as Bitcoin exchanges.
Regulators from various jurisdictions are taking steps to provide individuals and businesses with rules on how to integrate this new technology with the formal, regulated financial system.
But have you come to think of it... Whether Bitcoin can be used for illegal Activities...
What are some ways you think it can be used for? (illegal Activities) mention some.
Some people are using bitcoins for illegal purposes but you should not forget about majority who are common people and using it as an investment medium. Governments are actually benefiting as they are getting more tax from these people making profit with bitcoins.