[RetroTechie]

1) Power saved scales with # of devices. Even modest savings can have a massive effect if it's software that runs on billions of devices.

2) There exist many, many more client devices than datacenters. And

3) Expect software on client devices to be generally less optimized than software deployed in datacenters.

In other words: measure, and do the math. And ofc Jevons' paradox may apply.