And no, we don’t have a uniform commercial code (a fact that the sovereign-citizens simply do not believe when their documents relying on the UCC are rejected by Canadian courts).
Each province (except Quebec) has a Sale of Goods Act, which are all originally based on the English Sale of Goods Act from the 19th century.
The leading text on Sale of Goods is Benjamin on Sale of Goods, first published in the 19th century and now in its umpteenth edition.
In the UK we have a rather odd legal situation with Scottish and N. Irish banknotes. Both countries issue their own and if you visit either country you may find that you get some in change. The problem (which is largely theoretical) is that those notes are not ‘legal tender’ anywhere.
In practice, since they are always accepted in those countries, and fairly often in England and Wales, this doesn’t matter. Tourists do sometimes find that a Scottish note is refused in England. This usually has nothing to do with their legal status, but simply that, especially to a small business, they are an inconvenience and they can refuse to take anything they don’t like. Of course, the further South you go, the more likely you are to find a clerk who thinks you are trying it on with a foreign note.
My reading is that it would prohibit using currency that is not currently recognized as either Canadian currency or currency of another country when payment is called for in the form of currency. (Bitcoin? Counterfeit currency? Privately-issued currency?)
In Aus, Bank Notes were notes issued by Banks. In India, Note-of-hand was a note issued by an individual in the informal banking system. Both have been suppressed by legislation similar in effect to that quoted above.
That’s because the Confederate States of America were not the United States of America and no longer exist. USA currency retains face value forever, but the USA is not required to recognize the validity of CSA currency and in fact does not.
In Vermont (which borders Canada), Canadian coins valued at a quarter or less are more or less regarded as their U.S. equivalents by banks and retail stores. I am not aware of Canadian paper money being accepted anywhere. To obtain it, you would need to go to a bank and the transaction would be subject to the exchange rate.
I also recall that toll booths in Maine, which gets a lot of tourists from Quebec, have signs stating a different valuation for Canadian dollars, but I haven’t been there in a while.