With a lower profile (and a sealed top deck) the kayak stays much drier, making it less easily influences by crosswinds and far more navigable on large, choppy bodies of water. A kayak is narrower then a canoe but feels more stable. There's also less boat to push through the water, which mean less effort is required to produce more speed. Probably the most important element, however, is the advantage of being on your own, propelling yourself according to your own skill level but still able to enjoy the company of others while out on a trip. One of the biggest skills required for tandem canoeists is communications between one another. Time on the water can soon become extremely stressful if you're not getting with the other person sharing the canoe with you. You could go solo in a canoe of course. But the perception of solo canoeing is that takes far too much skill to master. There are such things as two-seated kayaks, but they've been given the nickname "divorce boats" by the paddling community.
I'm not a kayak virgin. I've tried the sport before. I kayaked Philip Edward Island near Killarney and loved it. And I even kayaked Lake Opeongo in Algonquin and thought it was the best vessel to explore and camp along that particular lake. But I also canoed the same routes before and loved the time just as much.
Like the canoe, kayaking is a passion that grows slowly. But the more you paddle one the more the boundlessness of sky and water will summon you. I will definitely go kayaking again, if only to witness the huge horizons, or no horizons at all. There's absolute beauty where sky and water merge. On the Philip Edward Island trip I navigated through thick fog, with just the faint sounds of the surf to verify the shoreline was nearby. I pushed through massive swells, low bracing and combating see-sickness throughout the day, but loving every minute of it. I felt alive. It was clear that I was in love with my surroundings, a very natural landscape that would never have been so clearly introduced to me if it wasn't for the kayak.
But that's just it. I basically love being in a wilderness setting, and whatever takes me there is a mute point, as long as I'm there.