WooCommerce SEO is its own discipline. The platform ships defaults that are routinely catastrophic for rankings: faceted nav generating thousands of indexable URL combinations, product schema emitted by both the theme and Yoast WooCommerce in conflicting forms, /shop/ archive canonicals working against the category pages, and a plugin ecosystem where every install adds another performance drag layer. Generalist SEO agencies running WordPress retainers usually treat WooCommerce as 'WordPress with extras' and leave the WooCommerce-specific work on the table.
The platform-specific fixes are not glamorous and they do not show on a ranking dashboard for the first 60 days. Faceted nav indexation control is the biggest single technical win on most WooCommerce stores and requires understanding the attribute model deeply enough to configure robots, canonicals, and parameter rules without breaking category navigation. Schema deduplication requires writing template overrides that play nicely with Yoast WooCommerce or Rank Math rather than warring with them. Core Web Vitals under WooCommerce load is mostly plugin discipline plus hosting tier; cheap WordPress hosting will undo every theme-level optimisation regardless of how good the work is.
Done properly, WooCommerce SEO compounds for the same reason Shopify SEO does: the platform's defaults leave so much on the table that the first quarter of foundations work recovers significant ground. From month four onwards the work converges with standard ecommerce SEO: content, on-page, internal linking, product description quality. But the foundations matter.