We have a setup where we have numerous case studies from our customers incl. testimonials from them. Many of these are specific to one of our products and we thought it would be sensible to include these in the "reviews" section of the Product Schema markup.
However, it is unclear to us if there is a practical downside to doing this and if it can result in penalties from Google.
From what we can gather, the idea is that the "review" and "aggregateRating" fields should be somehow linked to a review automation tool that is beyond our control. In practice, however, we assume this is very rarely the case for Shopify webshops (e.g. most review tools allow for moderation).
Does anyone have insight into whether there is in reality any difference from a SEO and penalty perspective between using e.g. a Shopify review tool vs. manually adding reviews from customers (which are visibly shown on the product page)?
I don't think there is any downside on Google's view per se for adding reviews by yourself. Just if you want to display ratings and some review info of your product page on the Google organic search results (yes it improves your SEO and google ranking), then you should make sure to have Google's review snippet in your product page as well.
But some notes:
The link to our app (it's free for all features): https://apps.shopify.com/farout-1
Let me know if you have any further questions about either your current issue or our app. Happy to help!
You cannot take testimonials (company reviews) and turn them into a product review even. Testimonials are not product specific and even if Google did award you Rich Snippets temporarily, you are at risk of a manual action from Google.
In order to receive the Review Rich Snippets, reviews must be submitted directly through the site (e.g. using a review app). Though you can migrate reviews from one app to another and you can approve or decline reviews, you cannot modify the review.
If you want to be able to utilize Review Rich Snippets for product search enhancements, you'll need to install a review app.