Virtually all oil eventually reaches the world market. Of course the Canadian crude doesn't go directly to the pumps, it has to go to the refineries first. Refineries..likely at places like Port Arthur, TX are connected to all kinds of distribution outlets, and can serve the US or world markets.
The advantage with the pipeline would be the 20,000 to 50,000 pipeline/refinery/oil industry jobs..plus the peripheral 500,000 or so jobs in trucking, manufacturing, hotels, housing, restaurants etc..
Plus the freedom from buckling under to an Iranian tyrant who wants to close the straits of Hormuz or do some other idiotic thing..
Besides all that oil money being generated and staying in North America, beats giving it to people in the mideast who hate and want to destroy us !