yeah, generally speaking, the admission to PHD is easy, but the graduation with a quality paper is difficult.for u know, the doctoral dissertation is considered to contribute the richness of world social or natural science.and your paper will be available in most of libraries, not like the paper u produce in china, which will be stored in some backcorner of the library. of couse, some paper could be also published if the author has a big chance in china.
personally, u must feel a need to get the PHD, if not, it's totally useless. if possible, do it spare time, and it will enchance your profile later.
u have to pay attention to what u want to read before the application, for in financial field ( assurance, markets, securities, banks, payement systems..), most of careers are supervised by a professional order, which means u must pass some exams to get a working permit. it is also possible that the master degree doesn't gurantee u of being admitted to sit the exams.
have u already started your immigration procedure? if not, this will take some two years, so time is also an important factor.
international commerce, if u agree, is not a major, for it's too general and too shallow. if i do business, i prefer a international lawyer, who can negociate, write and litigate if in need.
good luck