Meanwhile an infinite diameter conductor has a maximum efficiency of 100% with every part at whatever temperature you want. Carnot characterizes classical heat

Meanwhile an infinite diameter conductor has a maximum efficiency of 100% with every part at whatever temperature you want. Carnot characterizes classical heat engines and things that work a lot like them, it's not a universal limit of process efficiency and it's not even a good first approximation for many systems. Your example of a meaningless distinction is a factor of over two in waste energy, in the favor of Carnot in this case, but distinct none-the-less.