I think you missed most of the points in the post. To address your points which are well covered in the post (I'm guessing you didn't read it):
1) Printing bills is very expensive
2) Credit card payment networks are also very, very expensive (2.5-3.5% or more of every transaction)
3) Billions of people can't get credit cards.
4) How do you send printed bills around the world?
1) Printing bills is very expensive 2) Credit card payment networks are also very, very expensive (2.5-3.5% or more of every transaction) 3) Billions of people can't get credit cards. 4) How do you send printed bills around the world?