So VC is disabled by default in default Internet Security config. 2 new features & only 1 available & protects majority. Hope soon VC protects majority too.
Does VC works if Autosandbox is disabled?
They most likely decided to not enable it for the majority of users because it is so new and still under development and any issues with it could cause major destruction of data.

I'm sure they want it to mature some more before enabling it by default.
VC should be active outside of the sandbox, for example if you're only using HIPS, however during my testing so far I haven't been able to get VC to react on anything.. Not sure if it's a bug or an issue on my system, for now I expect the latter.