I don't know where they got this number, but it's actually very misleading. A click does not a sale make.

The whole point of this article is that you would've done way better if you could advertise on Amazon. When I released my book (which is actually in some of the same genres - political satire), I hired a professional marketing team and they leaned heavily into Amazon's paid advertising scheme. I just checked the numbers and found that they spent $270 on ads, and those ads generated $27 in sales. After I took over, I spent another $97 on ads, which generated another $27 in sales.

I don't think you missed out on much, and the self-published authors I interact with on Facebook are unanimous in the idea that doing paid ads on Amazon are a waste of money.