Magento2 officially recommend to use [Varnish on production](https://devdocs.magento.com/guides/v2.3/config-guide/varnish/config-varnish.html) as it's much faster than the built-in cache, but they don't describe why it's better than the Full Page cache and what are the missing elements,

so can anyone describe what are those things which are missing in Magento2 built inn cache and are available in Varnish? What are the core differences between these two caching mechanisms in Magento? >