“derech malbush”
This term can be confusing.
It shows up in the laws of Shabbos where it is used as a means of transporting items, even when one does not benefit from wearing them. Then we have the Shaatnez case where one puts on an item “derech malbush”, but only to advertize and sell the item. Hence, “derech malbush” alone without physical benefit is not enough to create a violation of Shaatnez.