I stopped needing gas long time ago but if I needed gas I sure as heck am not going anywhere where I can save $0.10 to pay in cash (probably spend 2x that in gas needed to get to the gas station to save $0.10 per gallon). or for that matter ain't going to any place that has a different price depending on my method of payment.
I was also going to say, between the Costco executive membership's 2% rebate, and CC incentives, it's probably a wash anyways between that or the 10ยข difference.