Seemingly, every non-motorized boat in the paddling industries can now be called a kayak. Throw in a double paddle and there you have it. People have found that using a single paddle for a canoe designed for one person is redundant; instead they have resorted to using a double sided kayak paddle. It is much easier to maintain balance in such a canoe with the double paddle. You are able to get more out of each stroke without losing consistency. The key to choosing which type to use is how you sit. If sitting on the bottom of the canoe it is easier to use a single, when sitting on a seat a double will allow you to maintain balance as if you were kneeling on the bottom of the canoe. In many of the single person canoes it is easier with a double paddle because you have more reach with the paddle. I higher stroke is also achieved, providing more power. Completing a j stroke with a double paddle is awkward but highly unnecessary.
If i had known this before i certainly would have tried it and may have even brought a kayak paddle with me. The fact that more power can be achieved is also very interesting. I really have nothing else to comment on, a good read but not much to reflect on and not much going away from the main points, certainly a well written article.