Paying with Bitcoin or any other cryptocurrency requires the customer to pay the transaction fees.
Regardless of what you think about credit card companies, which payment method do you think the average consumer would choose?
1) Pay by credit card, get 2% cash back, reserve option to reverse charges if vendor fails to deliver, don't lose all of your money if you lose your credit card.
2) Pay by Bitcoin, pay $8 transaction fee, wait 10-30 minutes for transaction to be confirmed, resubmit if transaction fee was too low, no recourse if vendor runs away with your money, lose all of your money if you forget your password.
Realistically, any crypto-as-payment service will either charge the merchants large fees (to cover risk, volatility, exchange, transaction costs) and/or collect profit on the exchange rate.
There's no free lunch, but the lunch is definitely not cheaper on the Bitcoin side for average transactions.