I get it they ride road bikes on gravel roads, whoooa.
Actually, I don't think that's the point at all. I think it's about touring the countryside just that little further away from the bitumen. From their home page: "Ride a MTB, a CX bike, a tourer, a roadie, whatever makes you happy." The riding ain't my style but I like the attitude.
I use to do something similar as training rides on the MTB. I quite like it as I like cruising back roads on a bike or a car, you get to see some cool stuff. Having said that, after getting a road bike a few years back I find it hard to do it on a MTB, it just doesn't feel right.