Doubtful for a few reasons:
1) If you're looking for specific category cashback (gas or restaurants), there are cards that do better on both with no AF (PenFed Cash Rewards for gas is 5% no AF, US Bank Altitude Go is 4% restaurants [versus 4% gas and 3% restaurants on the Costco card respectively).
2) Costco membership is $60 minimum which kills the value of the card unless you're already shopping at Costco. Costco.com allows non-members to shop at Costco.com with a 5% surcharge, so unless you're ordering more than $1,200 a year to break even against the $60 annual fee it's just cheaper to shop on Costco.com without a membership.
3) The Costco reward certificate is generally offered as a phone/printed/mailed certificate once a year at the start of the year to be redeemed in warehouse (this year with COVID-19 they made an exception and offered to mail people checks instead.) So if you can't get to a Costco warehouse reasonably (times of pandemic like right now are an exception which likely won't last) you can't redeem the certificate for any of your cashback.