More battery life for your Android phone
Even though your Android is “just a phone” it’s still a full-fledged computer with a CPU, GPU, multiple networking interfaces (WiFi, CDMA, EDGE, 3G, Bluetooth, etc.), RAM, ROM, multimedia, and display – and it does all this without being tethered to a power outlet all day.
In this context, complaints of battery life shouldn’t be a very big deal, but in today’s day and age, any smartphone (regardless of how awesome it is) should get a full day of “normal use” before it needs to be recharged.