The HK loophole doesn't make the ban total. The proof of China's commitment to the ban will be in the policing of it.

However, there is concern that Hong Kong is not covered by the new laws. It is a major ivory trading hub, with most customers believed to be mainland Chinese.
The territory is in the process of bringing in its own total ban.
China had already banned sales of ivory acquired after 1975, under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
But critics have long said allowing other ivory products to be sold openly drives up demand for the status symbol and allows illegal trade to flourish.