Hi, if you apply the upgrade after generating the rigify rig then it would be there, i just tried it.
And i have to agree there isn’t much information about this face upgrade and the benefits of using it.
And thats the reason i never used it yet,
You might be interested in this: https://blenderartists.org/t/found-a-facial-rig-solution-in-blender-eyelids-blink-with-non-linear-shape-keys/1369811