Kobel invents it to give Lumon a worker that could work without dealing with the extreme circumstances and pain (reasons why the townies are addicted).

People volunteer to do it to work with out feeling their current pain from external sources.

But what is the goal of Lumon in doing this to Gemma and Mark? It’s more than that. Their motivation is different than those other two examples above. I think it’s to create a new Kier heir to the Lumon empire.