Choice Auctions are a key part of the Pen based junct Sime economy. The Gens considered Choice Kills are either Wild Gens caught out-Territory, or children who were born and raised in-Territory by Sime parents and Established as Gens. Such Gens are self-aware, sensitive, and full of the will to fight.
Once overwhelmed by a Sime in Need, their terror is disproportionately satisfying to the junct in a way no Pen raised Gen could be. Therefore all the Gen Auctions, but particularly the Choice Auctions are vital to keeping the peace in a Junct Territory. Thus when the loose organization of Householdings called the Tecton takes control of the Sime Territories to become the selyn distribution system, they have a hard time eliminating the Pen System and the Auction system. But, within 15 years of the First Contract, they do succeed in becoming the Modern Tecton by pretty much eliminating the Kill and replacing it with Channel's Transfer.