I agree but for a different reason. It seems obvious that Maxwell's demon would itself use energy, thereby paying for the "decreased entropy" with this energy.

This is essentially the same as:

> The second vital piece of the puzzle was the principle of erasure. In 1961, the German American physicist Rolf Landauer showed that any logically irreversible computation, such as the erasing of information from a memory, would result in a minimal nonzero amount of work converted into heat dumped into the environment, and a corresponding rise in entropy.