Matches, aka Ketse, is the most valuable currency in the Kin-Dza-Dza universe, and even half a match is enough to buy a transportation device. The setting is dystopian/resource depleted ("we used our oceans for fuel") and the value of the matches are said to be "because of the chemicals" Wef is even shown scraping a match head in a scene.
So, why are those chemicals so valuable? Match technology nowadays is based on potassium chloride and sulfur, but in the movie they clearly have access to other sources for that, like wood and hair. Did the Soviet Union in the 80s use a different material for matches? (I don't remember them tasting any different as a kid) Why would it be precious in a resource depleted world?