Originally Posted by
yeunganson
The only legal tender currency for transactions in Canada is the Canadian dollar. The hotel cannot give you $US 10 because US dollars are not a currency allowed to do business in Canada.
There are Tim Hortons and Wendys locations that publish their exchange rate for US dollars on the menu. The hotel can simply apply 10 USD credits against whatever is being purchased, processed at the prevailing exchange rate. That's how paying with a Marriott gift card, available only in USD, works in countries that do not use USD including Canada.