Unfortunately, the Visa Mastercard duopoly charges fees which make this impractical, which means that via a cryptocurrency is how this would be implemented given today's technology.
Not to mention then taking on the role of judge, jury, and executioner on who is allowed to receive money. That's really not healthy for a free society
Or you could start off with macropayments and make micropayments possible later. Letting perfect be the enemy of the good is how we got here.