To be fair, the benefit is really uncountable. So many people here in HK dislike those from Mainland. If you go to TST/Central to ask the shopkeeper, do you know if they prefer people from HK or Western country or those from Mainland China? Easy, Mainland of course.
I have to save money for a year for a pair of ferragamo. Those from Mainland can buy a few pairs in a time plus Gucci handbag for a dozen. My 99's friend in Mainland China came to HK last week from GZ for just 4 hours to buy 2 piece of fur @ $20,000 plus dozen of baby food from Japan @ a few hundred.