Pretty positve the rolling resistance is the same it’s just that the larger diameter has the ability to roll over larger objects with less disturbance. In general I’m not convinced 700 is faster than 650 on a gravel bike because of the weight and geometry differences, it’s probably a wash on anything but super rough terrain.
Also I saw a MOG IRL, looked nice, didn’t seem to do any better or worse than anyone elses’ bike.