Pepsi cares about sales rates of Pepsi products in $localRegion when they run an ad campaign in $localRegion.

Major multinationals are sophisticated enough to correlate their ad campaigns with product sales. And they have the resources to run numerous ad campaigns simultaneously in multiple regions and iterate on the campaigns that work. Smaller players are less able to do that, and are forced to rely more on metadata like click through rates because they can't see the bigger picture.

Yeah - apparently it's called brand awareness - you see the logo, that's enough.

That's true, because click-through rate is not at all a good measure of ROI.

click through rates != ROI

Pepsi cares about making you read the word "Pepsi" over and over until you buy one, but you don't buy them from pepsi.com, you buy them at every restaurant/store you go to.