We always speak about privacy when we speak about ads. I want to point out something else.
Like JR-Fi already said, ad costs a lot. As very minimum a huge amount of energy - which we shouldn’t waste in times of climate catastrophe. It also costs so much life time for people who create it (increases world working load), it steals time of users and we all have a very limited amount of life time and should use it for something better.
Also think in therms like “what nice pictures could be on busses, if there wouldn’t be ugly advertise”.
Even if you buy something because you saw its ad before, you make economy not stronger because most of us have a budget limit. What you buy because of ads, you don’t buy somewhere else. And this way it’s only a very egoism business where few companies can grow up on costs of all others. And this way it makes economy even weaker, because its easier to attack a single point instead of hundreds of points.
And you know, on top come privacy problems. I think advertise (with data collection or without) will make our life worse - if we feel it or if you don’t see it in any way.