In my experience converting money either way costs the holder a pretty steep exchange fee. This fee applies bith ways. For instance, I heard the local airport (Dulles near Washington) had the lowest fees compared to other comerical services in the area. They charged me something like 18% to convert US $ to Canadian. Plus, I took more than I needed just to make sure I could cover something unexpected. When I went to convert the Canadian $ back to US $, I got charged 18% again to convert that back to US $
Alao, with many banks, at least mine here in the US, if you give them Canadian $ they may or may not take it and if they do they dont credit your account right away.
Also, you cant use Canadian $ anywhere in the US.
I also think some Canadian outfitters game you asking for US thinking you won't consider the exchange rate. For example, you don't see any US businesses listing prices in Canadian $ but every Canadian outfitter I have seen lists their prices in US dollars, even though they sre a Canadian business operating in Canada.
You don't see other countries listing prices in US $. Why does Canada do it?
There obviously a lot to unwrap here.