Ignoring the advertisers for a moment, it's obvious that companies have a legitimate interest in knowing what portion of their ad spend is reaching people who eventually become customers. If the tech evolves to the point where that metric is knowable by some means that also respects consumer privacy, then that could be a net win.
It helps that Apple doesn't rely on advertisers for the bulk of their revenue, so they can actually pursue this sort of thinking without gutting their business.
It helps that Apple doesn't rely on advertisers for the bulk of their revenue, so they can actually pursue this sort of thinking without gutting their business.