Ours come with us every trip. I built a rack (out of 2x4) for ours to ride in the truck bed, have to modify now that we're taking 4 instead of 2 bikes. We use them LOTS, everywhere.
On last year's trip to Utah & area, the "old" (road touring bikes with recent Bionx electric conversions) were found to be inadequate on many gravel roads & trails, so last winter we bought a pair of fat-bikes for desert/beach/rough country use. My own fatbike is in the midst of getting a second wheel set, 29er w/somewhat narrower tires than the "fat" tires, to swap in/out depending on where I'm going to ride.
Have to say, after a few years of declining bicycling (& accompanying fitness decline!), the electric conversion renewed both our interest AND our fitness level to the point where riding the fatbikes is possible, which it wouldn't have been otherwise.