Making 4% back on gas is mega killer though.
That said, I do kinda miss the Amex and its automatic extended warranty.
[0]https://money.cnn.com/2016/03/31/pf/costco-visa-american-exp...
The Costco Visa also include an automatic warranty extension of 2 years beyond manufacturer.
AmEx not listed anywhere.
Maybe yours does something different, or it's an AmEx branded debit card, or you're not in the US and they do something different abroad, but no Costco I've been to since the switch has accepted any credit card that isn't a Visa.