Commercially viable for Google boils down to can they attribute ads behaviors to it or not.

Then there’s a second tier of things that just make those wheels turn and if they do or don’t make ads revenue is nominally immaterial.

The teams doing this stuff at Google are purely for show, none of this makes it into any real products.

There’s the narrow exception of stuff like gboard, that does use privacy preserving ML/fed learning, but this stuff isn’t in the same zone.

I find it a bit embarrassing when Google publishes this stuff to be honest.