We all know that Bitcoin is also popular to criminals because they can use it without exposing their identity. It will be more convenient to them to use Bitcoin so that they can hide their identity. Do you think that terrorist groups like ISIS use it for their transactions?
They are technologically very advanced as compared to other such groups especially in the field of IT. They might be using it, but I think its not as beneficial to them as we consider it to be. And if they are using it, it doesn't make any difference.