I can understand not letting a rando off the street see the data, or taking extra measures to authenticate that you’re the actual owner at the time of the recording, but otherwise “privacy” doesn’t seem like a good enough reason.

More likely it’s “we want to be the only one who can see it.”

Semi-related: Reminds me of the time Amazon promoted a “recommend books to your friends” feature, and someone used it to make a recommendation to me with a vaguely threatening message attached. I asked them who it was and they screamed bloody murder about protecting customer privacy and I’m like “really? Privacy of your identity to a friend you’re recommending a book to? As a feature that you’re allowing to be repurposed into an anonymous messaging service?” (Eventually they relented.)