I mean I don't think I'm giving a particularly favorable view of the product

I expect AI ads to start with blindingly obvious overwhelmingly excited endorsments, but it won't take long for that to show up in the metrics that won't work very well past the initial intro, and they'll get more subdued over time... but they're always going to be at least positive. The old saying "there's no such thing as bad publicity" is wrong, and the LLMs aren't going to try to get you to buy things by being subtly negative on them. If nothing else, even if you somehow produced a (correct) study showing that does increase buying I think the marketers would just not be able to tolerate that, for strictly human reasons. They always want their stuff cast in a positive light.