This is interesting timing given the general decline of ad revenue due to the COVID economic slowdown. I'm surprised and impressed that they are making things harder for advertisers when then are probably fighting harder for every ad dollar.
It doesn't hurt that GOOG has an incredible amount of capital on hand.
They would rather establish a framework of proof that they control rather than have a more onerous and inflexible one imposed upon them by the EU. When large companies do due diligence to show accountability, it's less likely that a government will try to force them to do it.