Apple's answer to a camera-and-microphone gadget sitting in your kitchen: wall everyone's data off from everyone else, including Apple.
HomeView can recognize up to six household members by face and gives each one a personalized Home Screen with their own apps and widgets. Shared photos and music stay available to the whole household and guests, but content from Messages and Calendar only appears if HomeView recognizes the enrolled user's face and their paired iPhone or iPad is nearby and recently unlocked - with an exception if that paired device loses Wi-Fi but still shares location, cellular signal, and a recent unlock. Camera and microphone data gets processed in "Secure Exclaves" on the device's A18 chip, which Apple says are walled off from its own software, apps, users, and Apple itself. Siri requests are handled on-device or via Private Cloud Compute, which Apple says neither stores the data nor makes it accessible to anyone.
The real story here is the stakes of a shared device. A phone's privacy model protects one person; a device built for a kitchen or living room has to arbitrate between family members, houseguests, and an always-on camera and mic, which is a harder problem. Apple is essentially importing the Face ID-style secure-enclave trick and the newer Private Cloud Compute model, both proven on single-user phones, into that messier shared-household setting - a space where Amazon's Echo Show and Google's Nest Hub have offered profiles for years, with mixed privacy records.
Worth remembering: every claim here, including "Apple itself" being locked out, comes from Apple's own description. None of it has been independently verified.