For static handheld shots it really does not mattr much. But if you are using VR from a moving vehicle or shooting a moving subject them it is good to be able to judge how well the VR is working. If you can't see the VR in the viewfinder then you have to look at each shot in the LCD panel. Also you can simply see beeter if the scen in the viewfinder is stable.
You are right. it is the final image that counts. But if that is really true why are we using digital? My 70's vintage film camera (it's an F2) still beats any Nikon DSLR. So there must be something more then just the final image that we care about.