Let's try this one more time. If the United States government, or the government of any nation of your choice, passed legislation to discontinue the production of physical currency in favor of a federally run and regulated system of digital capital, what do you think the positive and negative effects on society could be?
Personally, I think it's a bad idea. One, even fiscally responsible people have trouble keeping track of their money when they're using a debit or credit card to spend it. There's something about having physical cash in hand that reminds us to be mindful of our limits; without that voice in our head, we run the risk of racking up personal debt, which contributes to inflation. Two, how would people keep and use their money outside of their bank accounts? For instance, instead of storing money in a coffee can, would we able to set aside digital currency in a USB drive, or does every cent have to stay inside of a closed system? And what's to stop the government, or anyone else for that matter, from tracking every transaction you make? Three, it's already hard enough to keep counterfeit physical currency out of circulation. Counterfeiting digital currency could be even easier, and destroy its value.
On the other hand, it could eliminate or massively reduce the cost of minting currency. Considering it costs more than a penny to make a penny, this would be a definite advantage.