I would say this is a true statement, unless you already have found an award you like. For example, I am using DL miles to basically fly from MSP to Europe and Anchorage in F/J for 100K miles. That is a really good deal, assuming you are flexible and you already know the low-level award exists.

I am also using DL miles to fly between EWR/ANC/MSP/EWR with stops en route in coach for 25K miles (with the hopes of DL upgrades for PM members in the fall). One main attraction to DL miles is that they allow free domestic stopovers on their award tickets. No other domestic airline mileage program allows that, as far as I am aware.