I find it hard to believe that Surly would sell the CC with a triple crank minus the small ring. What would be the point?The point would be to simplify their inventory. One crank fits all.
But why leave off the other ring? Cost? Insignificant. Weight? Same.
Because the Cross Check is appealing to a different market than the Long Haul Trucker. You CANNOT have a cyclocross bike with a triple crankset. No one would buy it. Cyclocross is cool. Double cranks are cool, not triples. And if by chance anyone actually used the Cross Check in a cyclocross race, a double would work better. Front shifting during a cyclocross race is abrupt and sudden and forceful. You don't want the chain accidentally falling to the inner ring.