Sounds like they are ultimately looking to get rid of the customs forms handed out on the plane by having them filled out at the kiosks. I'm not sure if this ultimately would reduce lines or even agent staffing if everyone has to still see an agent.

I have only had to see an agent when using GE at IAH (not just the X, but everyone using the GE kiosks has to see an agent). At DEN and ORD, you just walk on to baggage and customs.