Very surprised that anything in Japan would ever be called USA or Usa.
Anyway that usage of "Made for USA" is all about tricking folks outside of Asia that if it's good enough for the United States of America, then it's a better quality made item than what's normally coming out of China.
Cheers, BB.
I live a 24 Hour lifestyle, but every now and again I seem to fall asleep, well at least that's what my wife tells me.