What does that have to do with anything?
They are effective giving .25 more points per dollar spent on the CA version of the card rather than the US because of the forex. For example, if I spend $1.20 USD on the US card I would get 1 Amex MR point, if I spent $1.20 USD on the CA version of the card I could get 2 MR points. Its a very simplistic example because you would incur a 2.5% forex fee, and I am including the fact that they round up, but just think about the spending that is done in CAD, at 25% less than the value value per dollar in the US.
Amex obviously realizes this, which is why there is an unpublished policy that you can transfer your US MRs to CA once per year
at the given exchange rate. So, I could get the Biz Plat 150k, and turn that into a whopping 190k Avios via this method.