It will drive alternative electronic currencies that aren't traced through banks. (maybe?) It might just bring back cash as a popular tool. I still tend to favor cash. A coworker's son works as a server at a local restaurant. A few weeks back my coworker mentioned she is concerned because he is keeping the cash from his tips - not depositing it. Apparently the son has close to $10,000 in a drawer in his room. My coworker is getting a little concerned. When the coworker mentioned this I just thought it was a little odd and a little risky. But who knows, maybe the kid is ahead of the curve. Glen Frey had it right back in 1984 "You've got to carry weapons, 'cause you always carry cash..." ;-)
The kid sees the problem, but cash presents its own dilemmas. If he’s found/caught with more than 5K in his possession, they could potentially cause him problems to the point to confiscation. Guilty until proven innocent.
There are historical examples of methods used to flush out hidden cash, such as the ‘old franc/new franc’ remonitization that the French did after WW2.
The hyper-volatility of cryptocurrency will look more and more appealing as time goes along.