I’m personally of the opinion that everyone who works in software should have to rack a server and bootstrap it. Physically mount it, cable it, and get the *nix distribution of your choice running on it, serving Hello, World.
Everywhere I’ve worked, there is a marked difference in the quality of engineers who had played with hardware - even those who merely had expressed interest in it, and maybe had an RPi - and those who had not. There is something about physically touching the thing that runs your code that makes you better at it. Maybe it’s a correlation between “wants to play with something unnecessary but adjacent” and “curious enough to ask why more frequently,” but I swear, it exists.
But you don’t really want lots of idle or underused servers, aside from burst capacity management. So if they universally and consistently wrote more efficient code I’d expect a smaller datacenter. Full of still busy servers but just less of them.
He gave them a lengthy, grueling, hyper-detailed tour of the entire facility, encompassing the HVAC systems, electrical systems, network and computing systems, finishing with about 20 minutes where he had them stand inside a hot aisle that he was just outside of, giving a fantastic soliloquy on the importance of code efficiency, and the consequences of ignoring it. It was hilarious to watch from the comfort of the cold aisle, knowing full well what he was doing.