This tab will help you to set breadcrumbs for your pages and posts. Only switch this option on when your theme is not adding breadcrumb already.
This tabs also allows you to set custom trail for your custom post types. i.e. you can change how your portfolio appears in schema. You can either select to have portfolio category in the trail of portfolio or you can choose to have your portfolio based on tag.
Additionally there is Breadcrumbs Ruleset, you can either include some thing or exclude for breadcrumbs to show in Google.