I've known a number of people over the course of my lifetime who bought with cash and they were normal, just wealthy. Once upon a time, paying cash allowed you to negotiate for a better deal with a business owner. I suppose that's still true even today with a business such a jewelry store.
It is NOT done , when one buys a piece of jewelry from the likes of Harry Winston, Tiffany & Co., or Cartier. Neither can one haggle / get away with avoiding VAT, when purchasing jewels in England, France, or other European venues.
Revion,Maxmillian, Saks Fifth Avenue, Neiman Marcus, Bloomngdales,and the now defunct Best & Co., and Bonwit Teller's do NOT give one a " seal " for paying cash for a fur. Nether do Haute Cuture houses ! They will give " deals ", but NOT for cash.