It’s odd that you think the people implementing the banners want them so they can get more data. They want them because they provide a shield from litigation. I don’t know about you, but in the past year, most of my ads on Facebook are from law firms with headlines like “have you browsed (insert random minor e-commerce site) in the past two years? Your data may have been shared. You may be entitled to compensation.” If I’m a random mom and pop e-commerce site and I do not add a cookie banner, and I use any form of advertising at all, then I am opening myself up to a very expensive lawsuit - and attorneys are actively recruiting randos to serve as plaintiffs despite them never being harmed by “data collection.”

It’s that simple. That’s the situation with CCPA. Not sure the exact form that GDPR penalties take because I’m not European. But it’s not a complicated issue. you have to display some stupid consent thing if you’re going to have the code that you’re required to have in order to buy ads which take people to your website.

Note that plenty of these cookie banner products don’t actually work right, because they’re quite tricky to configure correctly, as they’re attempting to solve a problem within the webpage sandbox that should be solved in the browser settings (and could easily be solved there even today by setting it to discard cookies at close of browser). However, the legal assistants or interns at the law firm pick their victims based on who isn’t showing an obvious consent screen. When they see one, it’s likely that they will move onto the next victim because it’s much easier to prove violation of the law if they didn’t even bother to put up a cookie banner. A cookie banner that doesn’t work correctly is pretty easy to claim as a mistake.