1) you trust Costco not to rip you off
2) you get 2% cash back as an Executive member
3) you get 2% more cash back if you use your Costco Citi card (some other cards offer 3%)
4) they hand you the gold
You can buy gold at spot price, no premium added, AND get 4% back. Then, when you need to trade bullion for bread to make squirrel sandwiches to survive, you're in good shape.
That's the ultimate in Costco for oldies. Ask me how I know.