A fixed connection between Russia and US would definately provide a boost to the Russian Economy, and probably would increase the US trade deficit as low wage produced goods in Russia/Asia could flow even more cheaply into the American market. Thats not to say that a fixed pipeline could probably be added in the tunnel which would prove to be useful for oil - thats is oil is still around by the time the tunnel if finished.
Canada is just an after thought in this arangement. If there was no US, this tunnel would not be envisioned.
My point to Russia and 'inline', was moreso in today's current environment, they choose to take the other position from the US to be seen as independant and not towing the US's line. They also are more friendly to US enemies, with the eye on lucrative military contracts. Since this tunnel would be very advantagous to Russia, and the costs have to be shared, it could act as a carrot dangling infront of a lumbering stubborn giant.