The provided "moisture meter mythology" link is a great example of why I started this thread. It lists so many points of uncertainty that it can make competent people wonder it a meter is worth it. I know I was on the fence about buying one.
My first point is that it did allow me, a first timer, to find hidden water with remarkable ease. I suspect many in the sailing community have the critical thinking ability to make good use of such knowledge.
My second point is that the meter is less ambiguous than the "mythology" link would lead one to believe. It may not be a crystal ball but it is a bit like having x-ray vision. I found that to be very cool (and helpful).