Vanilla worldborder has the advantage of being more aesthetic and more ergonomic for players but has the disadvantage of not beeing safe (spectator gamemode can pass trough for example).

Adding an option per border to synchronize the vanilla one with the CB one would be nice. This option would probably only works on border with a square shap

Unfortunately, there is no longer this option, why?

Unfortunately, there is no longer this option, why?

This was replaced with the chunky worldborder and chunky border add commands, which can be performed easily per-world.

The config option was hardly ever used and caused more problems and confusion than it fixed.

@Over2Craft-mc Latest dev builds have the border configuration sync-vanilla which will sync the vanilla world border with CB when added (aka will not apply to borders added prior to setting this to true).