I see what you mean about using multiple flyers in order to maximize the efficiency of the CPC, rather than focusing on CTRs. At the same time, though, paying attention to the CTR can be important to guage the effectiveness of the ad. If no one is clicking on it, it doesn't matter that it only cost you 5 bucks. Your money would be better spent trying to maximize how many people actually click on your ad, and can therefore be potential conversions, rather than just looking at ways to save on the CPC. If your ad is seen close to 10k times, and only one person clicked it, I'd think that you need to reevaluate what your ad is.