I personally just think it has a harmful effect on the metaphor of being "off". For the longest time, a device being 'off' was synonymous with being unplugged or unpowered, rendered fully nonfunctional. We worked really hard to build the metaphor of 'sleeping' devices to compliment this, and I think letting Find My run while a device is sleeping is perfectly fine. I worry for the end user though, who now has to tabulate the capabilities of their device in their head every time they power off.