"A new influx of up to 700,000 bpd from Canada will dramatically increase U.S supplies and in turn drive gas prices down. A study from Energy Policy Research Foundation found a greater supply of Canadian oil could save Gulf Coast refiners almost $500 million annually in transport costs, which, in turn, would mean lower prices for consumers at the pump."
In other words, if we don't have to have trucks hauling the oil back and fourth, we will save money in the long run, not to mention the pollution saved from less trucks on the road.