What's the point of lightweight code with modern computers?

I think there are many. Some examples: * The fastest code is the code you don't run. Smaller = faster, and we all want faster. Moore's law is over, Dennard scaling isn't affordable any more, smaller feature sizes are getting absurdly difficult and therefore expensive to fab. So if we want our computers to keep getting faster as we've got used to over the last 40-50 years then the only way to keep…