Taxes are paid in dollars. You can see dollars as some sort of collective hallucination if you want, but that fact ultimately keeps them grounded.
end of story, right?
Why does the currency any given person pays their taxes in matter?
Sure, you can exchange USD, CND and BTC as much as you wish, but the point is that, within Canada, you can be certain that you can always pay and be paid in CND -- which can't be said for any other currency.