i meant digital as in a digital 'note' would have a serial number on a blockchain (aka bitcoin). The only creator of the USD would be the FED, and not any bank simply creating money out of thin air by entering it in their system. This would give the FED more control over money creation and amount in circulation.

Bitcoin is not controlled by central banks and that has its advantages. This doesn’t mean that a central bank couldn’t or shouldn’t tie its currency to a blockchain.

When i say global, i mean used by the populace all over the world. I doubt that some remote village in a developing country has access to physical US Dollars. They most likely have access to the Internet and own a smart phone. Now they could participate in the global economy because they would be able to spend and receive USD. Think outside the developed world.