I suspect it could be due to Japan requiring that cameras play a sound when taking a photo or video. Here's some background:
https://japandaily.jp/why-you-cant-turn-off-the-camera-shutt...
> Japan’s requirement for an audible camera shutter sound isn’t just a quirky design decision — it’s a deliberate policy meant to prevent secret photography.
Looks like it will be an infrared camera, so perhaps that changes the requirement?
A shutter sound I kinda get, that is simple to implement, but how is a video audio signal supposed to work?
This
>I suspect it could be due to Japan requiring that cameras play a sound when taking a photo or video.
That depends on what "taking a photo or video" means. If it only covers making a recording, then it won't apply to airpods. The same applies for faceID for instance, I doubt japanese iPhones are making shutter sounds everytime you pull out your phone, even though it's obviously using the camera.