Costco several times per month anyway, so filling up doesn’t even require an extra trip.

I guess the question is if you have a Costco membership why wouldn’t you just plan to fill up when you are there anyway? Do you enjoy spending more money for the same product?

If you live in a place where the line at Costco is an affront to humanity (St George, Lehi, etc) then I don’t blame you for not waiting for fuel, but the rest of us who didn’t choose to live in such a hellscape don’t have the same issues you do.