Oh joy, something new from the world of socialism to invade our daily lives.
One of the best things with our current currency system is the ability to keep a low profile in public. All of our bills are green with black writing, so when you have a stack of them together nobody really knows how much you have. That way you can open your wallet in peace without people looking over your shoulder trying to see how much you have. Now if you had a stack of those multicolored bills people could easily tell exactly how much you have, and then you're more likely to be a potential robbery victim, or worse.