Most people running Windows like having multiple apps running at the same time - and often, what's running in the background can drain your battery. In this latest Insider Preview build (Build 16176), we leveraged modern silicon capabilities to run background work in a power-efficient manner, thereby enhancing battery life significantly while still giving users access to powerful multitasking capabilities of Windows. With "Power Throttling", when background work is running, Windows places the CPU in its most energy efficient operating modes - work gets done, but the minimal possible battery is spent on that work.
My biggest worry with technology like this is that it affects unsaved work. Luckily, you're supposed to be able to turn it on and off.