Sorry for the confusion, but let me explain further
In the early days of X theme, it's the main builder is the visual composer. X replaced some of the visual composers and disabled some of its features (that includes front-end editor). In X, it was strictly for backend editor only and X Shortcodes (which is now part of cornerstone). Hence, if you use X and Visual Composer, then you can only use what's provided along with the theme.
Then when cornerstone became available, we added a feature in visual composer where the user can disable X integration and another option to enable front-end editor. But it doesn't mean visual composer will have integration and updates for new cornerstone features and new elements. So basically, visual composer is only integrated to old features and elements provided in X shortcodes. We provided those options so the user could disable that integration and use visual composer independently and as a stand-alone builder. And just a bundled plugin.