I also am a fan of MTB cranksets. In the mountains the 32 ring works well for me on extended climbs and the 44 ring is plenty on the flats and DH's. The 22 is the bail out, bit off more than you can chew into a headwind gear. The 22 is silly low but its good to know that if there is traction to be had, I can climb almost any road loaded. Spinning your legs off at 3 or 3.5 mph is way better then pushing a 60 pound bike up a never ending gravel road.
If you are planning to spend more time in the flatlands then it may not make as much sense.