I Know.
low in the water - easier to control - better balance
I have seing it on tv.
More manoevrable, and less likely to sink!
Better in whitewater.
I paddle whitewater in an open canoe and have found that it takes more skill to paddle a given rapid than it takes for a kayaker. That's why there are so many more kayakers and why so few open boaters run the really challenging (read dangerous) drops.
ENCLOSED TOP SIDE
because
more maneuverable
because it is thiner and easier to manoeuvre
easier to manover over the rapids