Comment by IggleSniggle

I think in context here, it’s about not making software that does more work than necessary. Aka efficient software.

Much software doesn’t need to be efficient in design, just efficient in terms of developer time. But if power consumption is a consideration, making the software itself more efficient in its design (if not implementation details) becomes more of a requirement.

And, finally, there’s always people writing embedded/firmware. The line between software and hardware is blurry.