Technically no, no one has to explicitly lose money or pay for these rewards. The economy is not a zero sum game. There are direct costs with handling cash for

Technically no, no one has to explicitly lose money or pay for these rewards. The economy is not a zero sum game. There are direct costs with handling cash for merchants, for smaller businesses these are often higher than credit card interchangge/merchant fees. There are also indirect costs like lower sales and consumers losing cash due to theft.