Informing people only helps if they have a choice whether or not to use the app/service.

In many cases, people are tracked by services they cannot really avoid. One example is the German "Deutsche Bahn" app, which is full of trackers. Some organizations are now trying to fight this using legal means. Another example was the Covid vaccine registration page in my canton in Switzerland, where Google Analytics was being used (right on the page with my sensitive medical information). It wasn't even being mentioned in the privacy policy.

We have laws that say what's legal and what's illegal. If something is illegal, those laws should be enforced. Especially when users have no choice.