To satisfy current Chinese law necessitating Blizzard to show the odds of in game purchases, players in China can now buy Arcane Dust instead of card packs. This circumvents the law by having players receive a card pack as a free bonus to the dust that they bought.
Blizzard has previously said that the next expansion in Hearthstone will yeild ‘different availability’ of the most rare cards. Since the Chinese law took hold, a pity timer has been discovered as per publications,
however, it’s unclear whether these pity percentages will apply to the new bonus Chinese packs.
Players outside of china will not be affected by the new bonus packs. It’s unknown how well this new model is working, ever since Overwatch changed it’s loot box distribution due to the same law. It seems Blizzard may be trying to test the waters to see how strict these new laws are held by the Chinese