This saved me on an iPhone before. I lost my phone outside a bar miles from my house, and didn’t notice at the time. The next day I was able to track it and go retrieve it despite that the battery was dead. Otherwise I never would have seen it again.
I feel like this would help more than it would hurt, but I wish there was a way to force a full shutdown as needed. If someone is in danger, they shouldn't have to discard or destroy the phone completely to stay safe
I don’t know about the Android feature, but on iPhones, they reserve a little power when the battery is dead, or the phone is powered off, and it continues to be fully trackable. It functions like an AirTag by relaying off other nearby iOS devices.