If the LLM invents a product feature that doesn't exist, you have advertising fraud done fraud. And if the LLM un-invents a feature that does exist, you have done fraud and pissed off the advertiser.

To not have these risks, you need to play it incredibly safe. E.g.: The bottom half of the Vertuo Up's blurb is just off the website.

<meta name="description" content="Vertuo Up is our new fast coffee machine, ready to brew in just 3 seconds. Enjoy 6 cup sizes and app connectivity for effortless control. Shop Pearl White.">

This would've been on old-Google. If you're an advertiser, Google is going to charge you their premium rates for a sloppy first paragraph you could've put there yourself if you wanted.

Note how the search query in that example asks for a "compact machine" but the explainer doesn't say anything about the size of the machine. The dimensions are right on the product's webpage. This advertising product doesn't want to risk the LLM fucking up something like the dimensions, so it just does nothing at all.

And the kicker is that none of this has to be a problem. It's Google, they can just ask the advertisers to hand them over a standard-format datasheet, and put the LLM to work figuring out what parts of the data the user wants and include those verbatim. If the LLM hallucinates, it creates a perfectly truthful but slightly less effective ad. If the LLM doesn't hallucinate, you've created an ad product that is better than most product comparison sites, something users want to use.