This question have its answer itself,
everyone who holds bitcoins and want to buy illigal things buys with bitcoin.
Reason is simple no one can trace you.
I once tried to buy in dark web but actually i was ripped over there.
So yeah think before you buy almost 99% asre sacms
People with different interest will always create problem and there are some who see their business negatively affected
Can used bitcont to their advantage..