Yes, USD has been employed for illegal activities and that's not new for us simply because even this discussion board isn't produced however, we currently knew that USD or any other fiat is what is important that they used in performing illegal activities like buying unlawful things or make payment on criminals. I know that even the bitcoin is already accustomed to this kind of actions.

I prefer bitcoin than cash oviously.It's taxfree which is one of the major reasons which has made difference between bitcoin and cash making bitcoin more acceptable.Again,bitcoin swapping is a lot more simpler than money.It is safer as well.further,the cost of bitcoin is growing than money.Really,It is the most mordern currency to exchage,trading and commit.