Some countries in Asia have different standards and the failure rate can be much higher. Passing a FAA or Canadian Class I does not guarantee that it will accepted. You have to take a separate flight physical in the country of licensing. So if you get a Canadian medical and licenses you would have to convert them if you went elsewhere and that includes taking a medical. You can get info on this on the respective forums for the geographic region.
I would do the "foreign" medical when you are young because the initial medical is usually the hardest and once you have one, the renewals may not be as problematic.