So from first read it sounds like google is using bid stream data from their ad server, to inform suggested bids that would clear/win for customers buying this inventory through dv360/admob/adwords/whatever they brand buy side as now? Which sounds like a win/win for google, higher pub revenue, higher margin through buyers.
But other DSPs also have a large amount of bid data, even without clearing price on a loss notification (do any exchanges disclose?) they have so much scale that they can accurately price? If you're consistently losing auctions you know the clearing price is higher. But then I guess another problem is:
What about with first-price auctions?
This could theoretically help with bid shading if google does in fact leverage 'private' clearing data on what the true value of the impression is?
I guess that goes to the kind of unclear ethics of owning all sides of the transaction. Help your ad buyer win at a lower price by not bidding as high, but publisher loses out on revenue. Or the above up the price on all sides. I guess for Google it's whatever has the highest margin %