I always look at askance to USD-in-a-bank-account backed stablecoins. There's no innovation in them.
Their value also depends on how many USD's stored in that bank account (not transparent to ordinary people), and the inherent problem with USD - that the FED, a central authority prints it, remains still.
There are other - in my opinion more honest - crypto-only stablecoins, like Dai (of MakerDAO) or Augmint, which are not freezable by any authority, nor cheatable by bribed auditors. They are backed solely by crypto assets, all transparent.
Crypto assets are only valuable insofar as they can be exchanged for real world goods and services (mostly people seem to want US dollars). Purely crypto backed stable coins lack a stable relationship to the real world.
Those crime bosses eventually want to buy a new mansion, Porche, a yacht, jewellery/stuff for their wife/gf, you know, anything to actually enjoy their life in real world. They eventually need to exchange their ill-gotten gains for real money. They can't stay in BTC forever. Basically they want to turn the BTC they got from their criminal activities to a clean cash not linked to crime. There are various way they might go about it, basically similar techniques as money launderers use.
You could certainly accept bitcoin for black market transactions and spend bitcoin on black market transactions, but wouldn't most participants want to transport their gains to the real world eventually?
Their value also depends on how many USD's stored in that bank account (not transparent to ordinary people), and the inherent problem with USD - that the FED, a central authority prints it, remains still.
There are other - in my opinion more honest - crypto-only stablecoins, like Dai (of MakerDAO) or Augmint, which are not freezable by any authority, nor cheatable by bribed auditors. They are backed solely by crypto assets, all transparent.