I've heard that cash settled is an advantage.... but if something is cash settled, don't you lose the power of your margin? it seems that a cash settled spx contract would be very expensive. from a risk management perspective, that seems harsh. i.e. being required to buy spy (if assigned) would use less cash resources than being forced to cash settle spx without any margin power. am I missing something? I know that buy/selling options on spx have better lower initial margin rates, but it seems it cash settlement quashes that advantage. am i missing something?