You got it in one... A lot of people come to Dubai from neighbouring countries and also rich people from Africa/Asia to Dubai, where a lot of European/American shops do not exist. They are the ones who would be buying from this store...
On a footnote, the Telecommunications Authority of UAE has blocked FaceTime on iPhones and iPads, on some religious pretext or another. My iPhone which I bought it through du has FaceTime blocked. My iPad which I bought from UK has FaceTime working. I wonder with opening of the official Apple store, will it mean removing the FaceTime block...
Also people talking about turbans/ghutra's and burqa's need a visit to Dubai !! You will be hard pressed to find local people wearing traditional dress, working in stores. Except for Banks and Government institutions, you won't find many places where you would see locals working. The Emirati population is less then 10% of the entire population !!!
Also the Emiratis in general are extremely well educated (either UK/US), very polite, very gentle and helpful. I base my opinion on a few number of local people that I personally know and they have been nothing but extremely helpful, humble and respectful.