I don't think the Japanese story offered enough by itself to stand alongside the rest of the plot as an individual entity. It meshed incredibly well with one of the central themes, the anarchy caused by communication breakdown.
The club scene really hits it out of the park for me. And her walk back home, walking past the musicians on the street. All in total silence. I love it
Oh, and I think the look Brad Pitt gives that helper dude when he refuses the money... moving