Google App v9.10 update include “Face Match” code for identification by facial recognition, akin to what is obtainable with Apple iPhone X and XS models, though the feature won't be limited to smartphone access, but also other Google Assistant enabled devices.
Google has been exploring deeper into facial recognition technology, which it pledges to keep free until there are enough policies to prevent abuse of the technology, inline with its commitments to responsible development of AI (artificial intelligence).
Face Match, though would require devices to have an onboard camera, so may not be supported by Google Assistant on Google Home product line.
Albeit, Google Home Hub comes with the rare voice-interactive smart display, but still without a camera, and utilizes Voice Match and interaction by voice; so the face ID would not offer it much in the way of personalized enhancements.
The Face Match support forecasts will make security an increasing focus for voice assistants in 2019, and as a second-factor authentication when Voice Match fails to work, Face Match could be the key to unlocking your smart display.
Google, it is believed will not only support on-device recognition in the long run, but also across Assistant-enabled devices with the proper hardware or even detection for multiple-user devices.