You do pay the price for using a real creditcard with the interest and etc... that you have to pay when using the card, Although most don't charge a fee like what you do voluntarily with BTC but still you pay more than these 3 cents overall and with using the card, other payment processors like PayPal charges ridiculous fees "+0.3 cents and a percentage per payment" so I don't find it outrageous at all to pay 3-4 cents for the miners.