It's pretty simple really.  VISA, mastercard, American Express get a fee for every transaction they process.  These fees range from 1-3% depending on the credit card company.  By campaigning for a cashless society they are ensuring that they collect more in fees from businesses that were previously cash only.  As it stands right now the cost of using visa (or the other companies) is absorbed by the business.  In a few rare instances you can find places that give a discount for using cash, the discount is because the transaction fees are saved.