I think you're missing the point. Unlike in the case of an ideal Turing machine, nothing in this universe transitions through states without energy. Computers rely on the power grid to run their processor cycles, even though I doubt that you would consider computers to not be Turing complete.

This is not that different from the Excel example: the system displays Turing completeness if supplied a clock as input (a person clicking a button in the spreadsheet, for instance). The human is not making any decisions in this case - the logic manifests itself entirely from within the system.