Isn't it obvious? It's tech companies and mobile ecosystem. Everything that can be used for ads and surveillance, will be used for ads and surveillance.

Pose detection can provide a lot of insights about the user's overall health. All the unscrupulous players now need is some bullshit reason to convince the user to a) install their app, and b) use the feature. Like, idk, high-fidelity dancing AR avatars to use as stickers on social media (a real thing, btw.).

Apple may or may not make this hard, but it's a real thing to be concerned about. Arguably, it's the most obvious use case, given the state of this industry.

Yes, the reason is I considered it funny. Sorry if that didn't work.

Also, I didn't downvote your comment, but I just upvoted it to compensate for someone who downvoted you, seemingly without a good reason – at least I agree with it.