There is a quiet little secret in paid media: click-through rate is mostly a proxy for whether your creative is misleading.
High CTR can mean the ad is great. It can also mean the ad is making a promise the landing page cannot keep. The way to tell which is which is to measure incremental revenue against a holdout — and most teams do not.
Why this persists
CTR is daily. Incrementality is quarterly. Daily metrics get optimised because daily metrics are what humans see. The only fix is to put incrementality on the same dashboard, even if the number lags. It changes what the team chases.