|The science of wrapless baked potatoes is sound from the perspective of heating efficiency, but in the kitchen and in the woods, sometimes science gives way to other considerations.
I recall baking potatoes and other foods, including chicken and vegetables, in the coals of a campfire as a Boy Scout. In fact, the Cooking Merit Badge including a section on aluminum foil cooking--my Merit Badge Counselor at (the late) Loon Pond Camp, B.S.A. in West Bridgewater, MA and at Camp Sayre, B.S.A. in Milton, MA certainly emphasized it! Although the foods would have cooked faster without the foil, the obvious primary benefit of the foil was to keep the food (relatively) clean.
Even in a home oven, arguably the potato wrapped in foil would maintain more of its native moisture than it would if unwrapped. There's a bigger error bar for cooks who are distracted by small children, telephone calls, etc., and who leave the things in the oven longer than planned!