seems OP is not talking about compensation of the deal itself but rather compensation for the actual flight rather than a $100 voucher. Assuming his flight to Brazil was much more than that
If you book a hotel room for 1-7 August to visit a conference, would you be okay if they said "oopsie, it'll be available for you 10-17 August, here's a $100 compensation"? What about a rental car, or food delivery? Is it okay for your wedding photographer to show up a day late? Of course not, the product you bought is inherently time-sensitive.