That is it in a nutshell.
Not only does your static leakage go down with lower temperature, but you can also further reduce the operating voltage as temperature declines which in turn reduces power consumption (static and dynamic) all the further
Which leads to my suspicions about ""At 80° and Nominal speed, this chip will consume 7W"
If that is correct, SDP is just a marketing ploy to impress the world with something we already knew...
"Keep it cooler, and it will consume less"