It was on number 1 on the western storfront for several days (it's now on third, still impressive for a pre order), but the Chinese storefront is noticeable because it's competing with super popular games made by Chinese developers that just released on it.
For context; Cathay was announced for the game, which is basically Imperial Ming-Dynasty with a backdrop of mythical Chinese creatures and legends in the Warhammer world. It's never been seen before, in the lore and the tabletop, and CA is working with Games Workshop to put them finally in the Warhammer world as an actual faction. Some people have accused CA as pandering, but Cathay has always been super requested even when Warhammer was mostly in North America and Europe.
I would imagine the huge attention the game is receiving, particularly amongst their fans in China, is making CA very happy for the choice they made to include them,.