People in other countries have had multicolored currency for years. Australia even has a hologram. It's a way to combat counterfeit money and I think it's a good idea. Now we need to make the bills different sizes. It's interesting talking to someone who is sight impaired from a different country and they ask how someone sight impaired from the US knows the difference in denominations. I'm not sure how they do that
Of course the problem is that there is still so much of the "old" currency out there so people can still counterfeit and get away with it.