If you’re using one those plugins you might stumble uppon a notice in Dashboard about need of providing purchase key.
WPBakery Page Builder (the same applies to Revolution Slider) is included in theme on extended/developers license, which means we bought it for a higher price to be able to include it in our theme. You as end user can use it only with this theme, and do not get the license key that is used to auto-updates.
Updates of these plugins come with the updates of the theme (We always include new WPBakery Page Builder in theme few days after release). You can of course buy your own copy of VC if you want it faster or need support from plugin authors, but that’s not necessary.