In the specific case of batch processing, I hear you. Machine time is extremely cheap compared to engineer time. Then there are interactive programs. With a hu

In the specific case of batch processing, I hear you. Machine time is extremely cheap compared to engineer time. Then there are interactive programs. With a human potentially waiting on it. Someone's whose time may be just as valuable as the engineer's time (morally that's 1/1, but even financially the difference is rarely more than a single order of magnitude). If you have as few as 100 users, shaving off seconds off their work is quickly worth a good chunk of your time. Machine time is cheap, but don't forget that user's time is not.