Software developer here. I haven't done anything like this with iOS, but back on Windows Phone, I would have been one of those developers who used an anonymized account ID, but not tracked my users. Let me explain:
The account ID was developer/user account specific, so every time any of my apps (from my specific developer account) would request it, it would give out a hash that was user specific. I used that instead of a login system. I used this ID to store data to the cloud, and even if the user reset their phone I could sync the data back to the app because it was the same anonymized account ID. My privacy policy was that a users data was theirs, but it was (optionally) magically backed up to the cloud for their convenience. That data was never accessed by anyone except the user who stored it, and was never used for any other reason.
Meanwhile, if I used e.g. Google Analytics, I would have been giving Google access to user tracking data, so I'd need to declare it in my privacy policy. That's a much much different use for an ID than data backup for convenience.
It's the same API, used for a totally different purpose. That's probably why Apple can't blanket state that the use of an API equates to a specific privacy flag.
The account ID was developer/user account specific, so every time any of my apps (from my specific developer account) would request it, it would give out a hash that was user specific. I used that instead of a login system. I used this ID to store data to the cloud, and even if the user reset their phone I could sync the data back to the app because it was the same anonymized account ID. My privacy policy was that a users data was theirs, but it was (optionally) magically backed up to the cloud for their convenience. That data was never accessed by anyone except the user who stored it, and was never used for any other reason.
Meanwhile, if I used e.g. Google Analytics, I would have been giving Google access to user tracking data, so I'd need to declare it in my privacy policy. That's a much much different use for an ID than data backup for convenience.
It's the same API, used for a totally different purpose. That's probably why Apple can't blanket state that the use of an API equates to a specific privacy flag.