If you're doing a circle trip entering via West Kowloon you still have the awkwardness of getting a qualifying ticket out to Macau.

Doing it the other way, a train ticket out to HK is easy to get, but you can't enter via the bridge because you are entering from HK. You have to enter the Mainland from Macau either via ferry to a qualifying port or at Hengqin. Gongbei, like Luohu, isn't open to TWOV entries.

Not quite the game changer it might seem when you look at the practicalities.

But it certainly benefits some. Like those in Hong Kong who want to take international flights from Shenzhen or Guangzhou.