Good perf per watt means more than just good battery life. It also means the laptop's fans won't be screaming like the machine is being burned alive when being

Good perf per watt means more than just good battery life. It also means the laptop's fans won't be screaming like the machine is being burned alive when being pushed, that the chassis won't get uncomfortably hot easily, and and performance doesn't fall off of a cliff when you're unplugged. In short, it's about balance, which I think is just as important as raw performance for most people.