Visa, the card holder is an International Company with national branches. Have you asked Visa Canada for an explanation? My guess is that the tax policies of Canada do not allow the same benefits as do those offered to US residents: the free night and the 15 nights, for example, that count toward elite status.
Can you apply for the US card even though you reside in Canada? Just wondering? Good luck and please post any answers that you get--we would all be interested in hearing the outcomes.