I think it was @josh mentioned in one post that the backend is no longer using elastic search, and its named that way for backwards compatibility.
@josh mentioned in a another post that returning the results from a search not only returns all fields for the matching rows, but also all matching rows for any referenced thing.
For example, if User has field UserOrders (list of type Order), a search on Users will return the matching users, plus the full details of each of their Orders, plus any thing referenced by Order.