Why not is a better question to ask. In any case why is because on mobiles, battery life or the lack of, is the number 1 bugbear of people. AV's in general do use a lot of battery as they do a lot. Having a battery optimizer can help by reducing battery use by switching off the internet when you are on the lockscreen a bit like like juice defender plus other battery saving tricks. I hope you now understand. (Not being patronizing as having read it back it might be taken as such.)