Yeah, I am in the US market. My impression was that impressions were much less popular campaigns to run. But that's really an aside, and I might be wrong. :-)
My point was that (by my understanding) an ad aimed at generating clicks or conversions was measured for success by whether it generated clicks or conversions. It wouldn't be redeemed by being getting a lot of impressions if it failed on those counts. If the advertiser cared about impressions, they'd be running a campaign targeted at impressions.
Well, CPC/CPx/CPO campaigns only pay on those events, so yeah, impressions are a cost only.
But those campaigns tend to predominate on low-value inventory, whereas the branding campaigns naturally want a higher end of the market for impressions and the demographics viewing them.
Non-CPM is where Google really shines, their click-through on CPC is, AFAIK, an order of magnitude above the industry average.
My point was that (by my understanding) an ad aimed at generating clicks or conversions was measured for success by whether it generated clicks or conversions. It wouldn't be redeemed by being getting a lot of impressions if it failed on those counts. If the advertiser cared about impressions, they'd be running a campaign targeted at impressions.