[jmd42]

I don't think he even needed to prove that.

Rather it's that, in the course of evaluating this case, the court has been forced to make statements clarifying how certain rules and principles in GDPR are to be interpreted. And this has, in effect, narrowed the way Meta etc can use data.

Which for Schrems is really his ultimate goal anyway - his case is just a way to force the courts to rule / establish legal precedent on broader issues.