Ecommerce SEO case studies are still one of the strongest commercial assets an agency or in-house team can publish, but AI search changes what makes them useful. It is no longer enough to show a traffic graph, mention a few rankings, and expect that to carry authority on its own. AI search engines are much more selective about what they reuse, summarise, and trust. That matters because many brands now want their case studies to do two jobs at once. First, they need to persuade human buyers that the work was real and commercially meaningful.