While fraudulent traffic is a very real and annoying issue, it's largely irrelevant when you're optimizing campaigns based on things such as ROI or conversion r

While fraudulent traffic is a very real and annoying issue, it's largely irrelevant when you're optimizing campaigns based on things such as ROI or conversion rates. If the traffic source does not pan out you either attempt to figure out why and fix it or simply move on to another. In this sense, while you may be paying for the traffic on a click by click basis, you're still effectively buying it based on achieving your goals. Additionally, buying PPC traffic is far more accessible then attempting to get things done on a pay per sign up basis.