This is particularly obvious for ads for stuff like coke: Everyone knows coke exists. Ads for it do not inform at all, they only manipulate.
If ads were useful to the customer, then there would be no need to embed them with useful services, let alone to force customers to expose themselves to them by turning of their ad blockers. It would not make sense to give customers a choice between paying for a given service or suffering from ads: Those are signs that the value of ads for customers is negative. If it were positive, you could even charge extra for them.
Despite being a very bad method of informing customers, ads might be defensible if they were the only one. But they aren't. Classifieds may technically be ads, but they differ fundamentally from others in that customers specifically seek them out. That indicates that customers do get value from them.
Another suitable method of informing customers are newspapers and magazines, especially specialized magazines and ones like Consumer Reports. Their interests are aligned with the customer because it's the customer who pays them.
Admittedly, there is a problem with those publications: Most of them also contain ads. That means advertisers can influence their reporting with the threat, spoken or unspoken, to no longer advertise in them. This is another way ads make products worse and obviously not an argument in their favor.
Advertising is communication and has no inherent usefulness; the value is in the outcome. The user isn't suffering, they're choosing a way to convert attention to currency as a way of paying for the content they want. It's a choice they willing make and having the option to transact that way is a net positive for both sides.