I saw the thickness on BusseCollector and thought it must have been a mistake -- so, the Off Duty is really that much thicker than the Heavy Duty. I own Active Dutys, and they feel plenty thick enough to handle any stress a normal person could possibly apply without a cheater bar (and as thick as I'd ever want in an EDC).

As you noted, the OD is simply too thick for what I'd consider a utility cutting tool -- it's too small to have the weight added by that thickness be useful for chopping, and for cutting, it would be more like trying to force a wedge through material than a knife. Perhaps there are real-world applications I'm not thinking of, but the OD almost seems to be a "fantasy knife" in terms of practicality.