Bitcoin has very few practical applications outside of the form of payment, but this is also a form acceptable to a few stores and countries. They are used only by criminals as a currency to pay for weapons, drugs, human trafficking, etc.
It's clear you do not know the criminal stereotype.
I can assure you fiat is used more on those activities and especially fiat in a black bag that change hands in a dark corner. Majority of criminals are not IT savvy, they have computers that is trimming with trojans and shit. If they try bitcoin, they will be hacked very often.
Hackers on the other hand is a different kind of criminal which are IT savvy and yes bitcoin gives them options to extract money safely. But how much % of the market is this type of person?