Since I got this original game through Origin, I can't speak on it. But I got CoT from Amazon that sent me a physical box. Inside was just a key to put into Origin. You don't have to buy Origin just like you don't have to buy Steam. They are just clients. You buy the games you play with said clients.
But if the original game was like Cities of Tomorrow box copy, it just gave you a code to enter into Origin to download the game.