Stealth is important to get your ordered product to your front door. It is mainly a vendor topic (because they have to package the order) but you have to pay attention to it too, in order to avoid getting into legal trouble because you chose a vendor who is known for his bad stealth.
The important difference between stealth and decoy is that stealth is used to make the pack appear as normal as possible and also conceal the smell of the drugs. The decoy is an item that is used to hide the drugs inside the pack in an attempt to mitigate the possibility that the drugs in your pack will be found. Therefore decoys are essential in international orders because these packages get inspected two times by customs (in the origin country and in the destination country). They are not that important for domestic order though because they do not cross borders.
So if you order internationally you should look closely on the reviews for the vendor (as described in the choosing a vendor chapter) and check if they uses decoys and adequate stealth.