Ghost Shells are no longer just cosmetic, they are now an item that can be equipped to your Ghost in order to imbue it with additional attributes, such as being able to identify nearby items and flag them on your HUD. The only problem with Ghost Shells though is they have a limited range - around 30 meters.
However, if you equip a Ghost Shell to a sniper rifle that has a good scope you will be able to boost its range considerably.