It does a fantastic job forming around a product inside of a package. This ensures all parts are protected during distribution, while providing abrasion resistance for the most delicate ones.
Polyurethane packaging often comes in the form of a foam that can easily be cut into pads so small pieces sit inside of it properly.
It offers an open-celled configuration that allows it to have a softer feel than other foams. Because of this, it is often used to protect small, lightweight, shock-sensitive products.