This ad from Travel & Leisure combines a compelling image with informative copy. It makes a good case: you should buy a waterproof camera even if you’re not a planning to take underwater photos because the camera might get wet.
The headline could have been larger and on the top of the ad. The assumption here is that the reader is going to stop and read the copy in the box.
Most ad agencies make the same mistake. They assume the reader is interested in their ad and is going to stop and read all of the wonderful copy they’ve written. The truth is that people are busy and ads are an intrusion. Advertisers are lucky if people even stop to read the headline, so the headline needs to be big.