TNSB is a Canadian business. Seedsman is located in the UK; they do not, as far as I know, use Canadian currency in the UK.
If you try to spend the loonies down here in Hillbilly, USA, most folks would refuse it (although I do see the odd bit of Canadian change, now and then, because some cashiers must only be educated to the level at which they have to go by shape/color, I guess).
Someone has to do a little currency conversion, somewhere. If paying cash, it's the vendor's problem. If using a credit/debit card, might be the third-party billing facilitator that they use, IDK. But it might cost them a little off the top. Not everyone wants to eat it, I expect.
EDIT: I possessed an Australian $50 bill for quite a while. Trying to convert it to something I could actually spend was largely an exercise in frustration. I found one bank that would do so, but I was told there'd be a significant delay (almost got the impression they would have to hand-convey it to Australia, lol) - give us the currency and we'll call you... at some point in the future. They also wanted $15 (USD, of course) for the exchange, which - at current exchange rates - would have been $21.80AUD out of the $50AUD... meaning I'd end up getting whatever $28.20AUD was equivalent to . I finally gifted it to someone else.
If you try to spend the loonies down here in Hillbilly, USA, most folks would refuse it (although I do see the odd bit of Canadian change, now and then, because some cashiers must only be educated to the level at which they have to go by shape/color, I guess).
Someone has to do a little currency conversion, somewhere. If paying cash, it's the vendor's problem. If using a credit/debit card, might be the third-party billing facilitator that they use, IDK. But it might cost them a little off the top. Not everyone wants to eat it, I expect.
EDIT: I possessed an Australian $50 bill for quite a while. Trying to convert it to something I could actually spend was largely an exercise in frustration. I found one bank that would do so, but I was told there'd be a significant delay (almost got the impression they would have to hand-convey it to Australia, lol) - give us the currency and we'll call you... at some point in the future. They also wanted $15 (USD, of course) for the exchange, which - at current exchange rates - would have been $21.80AUD out of the $50AUD... meaning I'd end up getting whatever $28.20AUD was equivalent to . I finally gifted it to someone else.