I don't know about having "silver bullet" advertisements be your landing page and text ad. It looks suspiciously like spam or some kind of con (think about the majority of "Work From Home" ads). Every reasonably smart person I know wouldn't trust "silver bullet" ads enough to seriously consider paying for the product being advertised. In the particular example, most doctors are supposedly smarter than the average population and so I think the conversion rate would be even lower.
I don't claim to know a better way to garner attention through advertisement than eye-catching (yet suspicious) claims, but I think the described method helps you determine the interest level in your product from a small subset (more trusting or naive, depending on your point of view) of your target audience, not your total target audience. Maybe there's a known "naive-to-total" extrapolator that I'm not aware of.