Don't know if this is related, but Coca-cola is bottled and distributed by Swire Pacific in Hong Kong, the same company that owns Cathay. Since Bonaqua is a Coca-Cola brand, it makes sense for Cathay to use Bonaqua. Evian used to be distributed by Coca-cola as well, but apparently the partnership ended in 2013.

On a related note - does Cathay offer any sodas not made by Coca-cola?