They show in NYC to have a real commercial credibility and also to have big exposure and a kind of « fashion credibility » in a way.
Longchamp in France is not really aspirational but if it works in the US, it may have an impact in France.
And I suppose they wants to be at Barney’s, Bergdorf and things like that.
It’s a bit like what Coach did when they came to London. It was for the cool factor and fashion credibility. Once the commercial success came, they went back to the US.
There are many examples like that: Burberry pre 2010, Lacoste...etc.