On grids where pricing declines due to more low carbon generation generating, there is no extra value. On grids where pricing declines due to more fossil generation running, that is the signal you want to avoid loads during those time windows.

At the moment, lower prices are not necessarily a guarantee of lower emissions. And so, if you want to orchestrate loads to move them to the lowest emission time windows (perhaps not prioritizing cost), carbon signal is the way to do so.