Martin responded that internally featured snippets is a completely separate system. He explained that the featured snippet will take a “self-contained”
answer that’s in a page and then place that into an “instant answer” type context and called it a “very simple thing.”
By contrast, Martin said that a passages type result would be a page that might not necessarily give a concise answer and would be more of a “blue links” type search result.
He then reiterated that featured snippets and passages ranking are not the same and are different systems.