@Itsjustme
It's not as good as it sounds, and it needn't be any worse than it sounds.
They have sponsors. Sponsors offer discounts that you earn with your miles. It's not like they just start sending you cash. So if you use Tin Umbrella Coffee Roasters or you plan to switch to Progressive Insurance, it might save you a little money, but it will cost you the difference between what you earn driving and the actual cost of whan you buy.
@Itsjustme
The privacy policy says they don't share any information except at the point of sale, when they confirm the information like phone number that you give the vendor to claim your discount.