Google Search Central's Products Structured Data documentation has been updated to clarify which product-related pages qualify for structured data.
The recommendations for using structured data for each product remain the same. Rich results still only support structured data for single-page web pages.
Google clarified that web pages focused on variations on a single product can qualify for rich results and benefit from having their own structured data.
"Use markup for a specific product, not a category or list of products. For example, “shoes in our shop” is not a specific product. Currently, product rich results only support pages that focus on a single product.” Google Search Central said.
Also, Google Search Central said the product variation page must be published on a "distinct URL" to qualify for a rich result.
“This includes product variants where each product variant has a distinct URL.” Google Search Central said.