I once read an article that says bitcoin is used as a payment transaction for terrorists and hackers. And maybe you guys in this forum also already know it. But here i want to convey my personal opinion in that matter. I think that internet and bitcoin interrelated. Many terrorists and criminals use internet .so also with bitcoin which used perpetrator However, despite all these issues, do people make concrete efforts to ban the internet? No. Not because removing and banning Bitcoin is difficult, but because the internet offers more positive than negative. For the same reason, we have to be more careful about our mindset for Bitcoin, because much evidence has shown that Bitcoin brings many positive, if not more, effects than the internet. Internet and Bitcoin are just devices that 'bad guys' and 'good people'. Fortunately, the world is filled with more people in the 'good people' category.
Bitcoin was to be used by criminals before it became more mainstream. They could be sent rather anonymously and were used as the primary currency of .onion black markets. I think bitcoin is still used in illegal ways but there are other coins now which are more anonymous like monaro.
At the end of the day bitcoin is just a secure way of transferring and keeping wealth that doesn't rely on a bank to keep your funds.