Protect your hands from the cold without losing the 'feel' of your paddle. The nylon pogies have velcro that attaches around your paddle shaft. This allows your hands to touch the paddle, whilst protecting them from the wind, if you need to let go of your paddle at anytime you can, and the pogies with remain attached to the paddle so you don't lose them.
When you don't want to use them you can just leave them dangling in the middle of the paddle.