You have noticed our "Bog/Moor Roads" in the north, right? They have descriptions, but they are really just unique buildings that give trade bonuses. Descriptions give us another opportunity to inform people about these sorts of interesting and relatively unique constructions. They don't really make the province roads any different, but they were mostly just short range roads to help carry heavy loads between things like a mine and a smelting facility or other such examples. Not long distance things so much.