The dumbest assumption I saw Amazon baiting people into was using Chase credit card points for purchases. You'd think spending those specifically on Amazon would be more efficient than just getting cash and buying from Amazon with that cash, right? Turns out it's the other way around, and by a large amount.

They often have promotions which can make this very lucrative. “spend at least 1 mile, get 40% off” etc

yes, I started buying with miles because Amazon was giving me more value for those than my current bank.