I love to play devil's advocate. Often, you have your head deep in something and you forget to consider the other party, playing devil's advocate helps that.

And you are right, there will be no guarantee that the buyer will respect my user's privacy.

The point I (badly) wanted to make was that more and more services are leaving Google Analytics and move their analytics to a more privacy friendly service. Only accepting Google Analytics causes the service to lose a lot more sellers. Granted, being on Andrew shoes, that requires more work (integrating with all these services).

In reality, what bothered me is that they should have been upfront about it. Having a clear message saying that all the metrics are required, before filling all the details would have saved me a lot of time, and I would have been ok with it.