I work in medical billing. Problems with this would be that insurance companies rarely pay the full amount of the bill. They pay a contracted amount. Another issue is that insurance will usually only pay from a medical claim billing form such as a CMS1500 or UB04. Most hospitals would not provide these forms to you and would only provide them directly to an insurance company. When the insurance company pays from this claim form they will pay the hospital not you. You also sign forms at registration allowing the hospital to bill your insurance. There is also language in these forms that you are responsible for amounts not paid by your insurance. Now say you try to tell the hospital you have no insurance so they will allow you to charge to your card. Once they do this you now want the money from your insurance, so you need the above mentioned forms. You have to now tell the hospital you have insurance so they can send said forms top your insurance. They send the forms and insurance pays them, creating a credit on your account which would in turn be refunded back to your card, voiding your rewards and gaining you nothing. Plus, as pointed out if you have paid up front then your insurance denies, the hospital has there money so they are unlikely to fight your insurance to get payment.