It is a fine line. There is much crossover.
A case can be made that packaging supplies includes items like tissue paper, bubble pouches / bubble bags, cut up cardboards, and bubble wrap that go inside a box or bag, to keep the contents safe for shipping, are packaging.
Products including shrink wrap and box tape and pallets are for shipping the box which contains the product and packaging supplies.
Shipping supplies include products like: Corrugated boxes, Tape, Edge protectors,
Cross Over Products
Crossover products include the box. Popcorn boxes and cake boxes are for packaging. Heavier corrugated cardboard boxes are for shipping. peanuts can be a cross over product as they often go inside the box for packaging. then the packaging box is placed inside a larger shipping box and more peanuts are added to keep the box from shaking around during shipping. Right! So you open the shipping box when you receive it. Then remove the packaging box from the protective shipping popcorn or peanuts. now you open the inside box and find your product safety inside another bed of peanuts.
Why is it important?
The reason it is important is for internet users to find the products and supplies they are looking for.