Most CPUs implement a strategy called “race-to-sleep,” where it throws all the resources it has at a computing task, to finish it as fast as possible, so that it can hurry back to a low power sleep mode.
For that reason, optimizing speed often improves battery life.
More speed means you can do more stuff faster
What stuff are you doing on your phone that wasn’t fast enough already?
Most CPUs implement a strategy called “race-to-sleep,” where it throws all the resources it has at a computing task, to finish it as fast as possible, so that it can hurry back to a low power sleep mode.
For that reason, optimizing speed often improves battery life.