My impression is that in all those cases the root weakness was that those criminals liked to feel sophisticated, "in the know". So those special apps (special, from our perspective, as in euphemism for birth defect) could spread by fashion. The smalltimes like to imitate the big ones while the big ones try to stay ahead of the curve, eager to pick up anything new from upstarts before they become big.
It might be my Hollywood education speaking, but criminal networks are supposed to lean strongly on status and respect (how could they not, given the absence of law enforcement which makes trust the only option) and this makes them vulnerable to fashion as a malware vector.
