well, if you are in a rush and don't wear neoprene gloves like the beginning of this video, it's freaking COLD.
I love hand paddling, it feels so pure. Rolling is generally easier, and they make great backup paddles, and cheaper than break-down paddles.
You give up some power and leverage but you are always bracing, making it harder to flip. I go back and forth between paddles and hand paddles, but mostly use a regular paddle especially in the winter. I have a few friends who hand paddle only, and its more common in the east than out west.