I imagine this is the beginning of the end of credit cards with rewards in the U.S. Unless Congress passes some relevant law (which would not surprise me).
Also if you are a millionaire and are having a hard time finding a place to rent, why not just offer to pay 6 to 12 months of rent up front? Even in NYC that tends to work.
The only reason I have a credit card is in case I need good credit in the future for a mortgage or something. Otherwise a debit card would suit me fine.