Google announced the shuttering of the Structured Data Tool in July of 2020. The tool was to be replaced by Google Rich Results Test which tests a page for its ability to display in Google Rich Results. The SEO community didn’t react well to this news given that the structured data tool validated more than just the schema supported by Google.
Provided by Google as a service for the Schema.org community the Google Structured Data Tool was moved to Schema.org Validator. The new tool continues to have the same functionality for fetching a page or direct script entry. Unlike the Rich Results tool It’s capable of testing for all Schema properties.
To compare the old Google tool and the new tool with code taken right from schema.org produced 1 error and 3 warnings in the old tool. The new validator didn’t detect any errors or warnings. The old Google program indicated no image was an error and address, priceRange and telephone produced warnings for service schema taken right from the examples on schema.org.
Judging by the results in the old tool Google It seems Google may have been validating the schema for the items they felt should be included in your schema even if the schema type wasn’t supported by Google. Comparing the two results in these images you can see that the Google tool reported an error for having no image and 3 warnings for info left out, however, the new schema validator returned 0 errors and 0 warnings because none of these items are required.
I have never been comfortable using Product/Offer schema for services like SEO so that is why it was a good idea to review the differences in the tools. The new Schema.org Validator is much more useful than the Google version because it validates the code to schema standards, however, Google results reflect what they felt their audience should have gotten for the schema to have met their audiences needs and wants.