Comment by bbor

I mean, many advertisers go through the Google display network without having Google target their ads (AKA run their bidding algorithms). Typically they go through other middlemen agencies, who indeed would need at least some of this data to make use of it, tho perhaps in some derivative form.

Still, you’re right that Google could be keeping it all for themselves and feeding it to their black box targeting services. I really strongly doubt that’s happening with incidental assistant snippets much less intentionally-eavesdropped recordings, but it is more plausible than this makes it seem.