Salut, iti citez direct din Google. Prima e "Preia", apoi "Preia si Reda".
Diferenta e in ce am marcat italic, plus ultima fraza, poti vedea cum vede Google Bot-ul pagina respectiva si cum vede un user pagina respectiva.

Fetch: Fetches a specified URL in your site and displays the HTTP response. Does not request or run any associated resources (such as images or scripts) on the page. This is a relatively quick operation that you can use to check or debug suspected network connectivity or security issues with your site, and see the success or failure of the request.

Fetch and render: Fetches a specified URL in your site, displays the HTTP response and also renders the page according to a specified platform (desktop or smartphone). This operation requests and runs all resources on the page (such as images and scripts). Use this to detect visual differences between how Googlebot sees your page and how a user sees your page.