Of course!
Criminals use Bitcoin as they use other technologies such as the Internet, smartphones, computers, cars, etc. I will say more: it seems absurd but criminals, as the first medium of exchange, use the Dollar!
Out of irony, the objection raised by some about the use that criminals can make of Bitcoin is at least ridiculous. People use Bitcoin for the most diverse purchases: homes, cars, technology, drugs, illegal material. In short, it is a medium of exchange and it is used like the others. So it's foolish to worry about the uses you make of money. On the contrary, we would have to worry if the money we use proves to be conditioned by a central authority, somehow castrated and therefore no longer neutral.
Andreas M. Antonopoulos, professor and author of books on Bitcoin, such as eg. Mastering Bitcoin and The Internet of Money, it is usual to explain this association between Bitcoin and "forbidden" purchases in this way: "People ask me, aren't you worried about the fact that you can buy drugs with this money (bitcoin)? As far as I concern I don't know any form of money you can't buy drugs with.
More specifically, drugs are the second most traded commodity after food in the world, and have been such in the last one hundred and fifty thousand years. If you couldn't buy drugs with your money, I would argue it's not actually money.
So one of the criteria of money is that you can purchase products and services and if you can't purchase the second most traded commodity in the world with it, then it's not real money. "
I don't think there is a better answer.
Furthermore, a great debate could be opened about what is illegal and what is not.
In a global context, for example, can cannabis purchase be defined "illegal"?
Definitely no.
In fact, there are states in which the purchase of cannabinoids and opioids is totally legal, others in which it is restricted and others in which it is absolutely forbidden, with penalties ranging from simple fine to, unfortunately, death. Think, in some countries it is illegal to even buy alcohol, while in Europe the ban is only for minors, in other it is even illegal to buy some literary genres!
In short, Bitcoin is an excellent payment system also and above all for the fact of being neutral, not conditioned by the policy of those who use bitcoins or who controls large capitals. The same cannot be said about the digital Dollar (or Euro).