Because impressions measure that Google was willing to show the page, and nothing else. On one content lane we ran, a coverage expansion produced a sustained rise in impressions from roughly 28 a day to roughly 156 a day, held over months, and produced no measurable increase in arrivals at all.
The reason is position. Those pages averaged a position in the forties. Almost nobody scrolls to the fourth or fifth page of results, so a page sitting there can accumulate thousands of impressions and never be clicked. The pages were not rejected by Google. They were seen and ignored by people, which looks identical in a coverage report and completely different in your revenue.
This matters because impressions are the first number to move and the easiest to celebrate. They move within weeks. Clicks, if they come at all, move much later. An operator watching the coverage graph gets a strong positive signal early and scales the lane, and the thing they scaled was the ability to be ignored more widely.
We had to formally withdraw an earlier internal claim on exactly this point. We had written that coverage is not a lever, and that was wrong: coverage moved impressions five times over and held. The honest version is that coverage bought reach and reach at position 41 is worth nothing. Quoting the clicks while dropping the impressions had made a real effect look like no effect.





