There is no good reason (economic, environmental) to not complete the Keystone XL Pipeline!
The Keystone Pipeline is planned for a total of 6681 kilometers (Approximately 4,000 miles). It was planned in 4 stages:

As you can see, it is 72% complete. Here is the map of the pipeline:

Source: Keystone XL Pipeline - Overview, Project Phases, Timeline (corporatefinanceinstitute.com)
You can read more at the source website listed above.
Keep in mind,
The oil from Hardisty, Alberta, Canada and from US oil added at Baker, Montana, will still get to refineries in Patoka, Illinois and Houston and Nederland, Texas; however, it will be more expensive to transport by rail or truck, not to the benefit of any consumer and adding risk of spills and impacts to the environment, even if a lower risk threat, still higher than for pipeline transport. The XL portion is a larger pipe size, further reducing the cost of transport.
A refined barrel of oil (42gallons) typically produces the following products:

Product % Use
Gasoline 45 Boats, Cars, Motorcycles, Tools, Small Engines
Ultra-Low Sulfur Diesel (ULSD)/Heating Oil 25 Agriculture, Transportation, Home Heating,
Refrigeration
Kerosene, Jet Fuel 9 Cook stoves, lamps, heaters, planes
Hydrocarbon Gas Liquids (HGL) 4 Detergents, paints, solvents, plastics, synthetic
rubber. Propane
Residual Fuel 2 Steam powered vessels, Bunker fuel, powerplants
Other products 13 Asphalt, tires, lipstick, waxes