Sometimes a "public reference" is part of an enterprise's contractual negotiation. They can then use this (Tim Cook's visit + quote) to garner future sales.
Having worked with Apple in Japan directly (not just engineering related work, but having worked with former Apple Japan execs), I can tell you that the relationships they hold with companies over there are valued internally. It's part of the culture, for better or for worse.
I can't state for certain whether it matters in the context of Cook's Tweet, but it wouldn't surprise me in the slightest either. Don't be so quick to cast it aside. ;P