I can assure you that pax both deboards and boards in HKT. It is not just a stop for e.g. refueling.

The idea is to offer Chinese pax a direct flight to HKT (to compete with all the Chinese carriers offering direct flights to HKT from even remote airports in China now - the number of Chinese A320 and B737 arriving and departing HKT during late evening/the night is quite impressing).