While earning rewards on paying the loan bill might sound fancy but the process and charges are so complex that it's probably not worth doing it.
Also, as others have suggested, if your finances are not well organized, this could lead you into a debt trap where you might start rotating money and get another card to pay the other card's bill. I've noticed this with someone and though I encourage utilizing your expenses, you should also know when to stop and just use netbanking/UPI to keep things clear! 🙂