One Audience, One Ad, No Segmentation
The default setup in most ad accounts is a single "website visitors" audience receiving a single creative. Someone who browsed your blog once and someone who viewed a product page five times, added to cart, and abandoned — both see the same ad. There is no logic that distinguishes intent. High-intent visitors are not receiving messaging that reflects what they actually did, and low-intent visitors are consuming budget that should be reserved for people closer to a decision.