Concern for models' privacy - model release

As @Jill_C said, model releases are for Adobe use only. The buyer only knows that a model releases is attached, and in case of a dispute, the model releases could be used in court. Adobe will not give out any information about the models in a picture, even if asked privatly. 

The hide feature is only for your use when searching for a release. Imagine having a 100 old releases and new pictures. You can hide the old releases, so that they won't appear when you search your releases for attaching to new pictures. If you photograph the same model in a new shoot, you will need anyhow a new release for that shoot.

That's merely your assurance that if a model tries to sue for infringement, the asset has a signed release form digitally attached to it.  This protects you, Adobe and customers who purchase the asset in the event of any disputes.

If there was no release form attached to it, that asset couldn't be used for commercial purposes. IOW, it would be rejected from inventory.

Model releases are attached internally in the Adobe Stock database to the related asset, and represents your assurance to Adobe that you have obtained the necessary rights to use a person's likeness. Adobe Stock does not make the model release available to Buyers.