Nexus advantages vs. CANPASS

So i've been browsing around and trying to find an answer to my question; it seems pretty clear, but I just want to cover my bases.
I travel several times a year from Montreal to different countries in the world (usually Europe). I have the option of getting the CANPASS card for one year and pay $50 or getting the NEXUS card for 5 years at the same price (plus the benifits of fast USA access).
It seems that they both provide the same benifits at the Montreal Airport, basically skip the line and go scan the eyes.

So, I'm thinking, the NEXUS is an obvious choice. I'm just not sure why one would choose the CANPASS over it since it's 5 times more expensive and does not give you any US priviledges. Am I missing something?