Didn’t Canada do the same a few years ago? It should be pretty easy to guess the effect on the economy according to their experiences.
Regarding picking up a penny from the ground, one of my teachers once mentioned that by picking it up you show Hashem that you value money, so he may send you more. (Hopefully the real stuff.)
Additionally, I think that because it states “In G-d we Trust” it’s not kavod to leave on the ground.
Just my 2 cents…