Yes, nowadays its being used in crime, they buy and sell online and pay by bitcoin. Because its untraceable. So police cant get clue to caught them. I think its dangerous.
Anonymity is indeed a feature of Bitcoin, both advantages and disadvantages, its user community is bitcoin anonymous, but some governments or countries is very difficult to accept, in fact, many criminal activities or need anonymity There will be some more anonymous currencies, such as Monroe, Dart and so on