Delta Pay with Miles program is available to anyone with a DL Amex card (included no annual fee Blue card) --
https://www.delta.com/us/en/skymiles...pay-with-miles
Miles would have at least have some value with a DL Amex card even if you don't use the miles for an award booking. You can generally do somewhat better with award bookings than the 1 CPM redemption rate you get with Pay with Miles. But either way, it's a bit silly not to earn miles (or refuse to redeem them) just because you might not be able to find a particular mileage redemption rate you are seeing on other carriers.