During the Unlocke Revolution, forgers created keys that solved many complaints. Keys were crafted to keep houses warm, or cool as needed. Keys were crafted for better travel – rich had even personal portals. Keys for growing better crops. For harvesting more efficiently.
Paying for these luxury keys was costly, however, and poorer households might only afford one Intrinsic key for each child. Usually, they would chose that which would guarantee them job stability. Like a tailoring key, gracing individual with skill to perfect clothing, or a musician key to entertain the wealthy, etc.
Royals had their own personal Key Forgers, and could purchase any key to their liking.
Only, sometimes keys—especially medicinal keys—did not work. The body had to live through the effects of some keys, and in some cases one couldn’t handle the transition.