Seems like waaaay more trouble than it's worth. Unless you're doing just a couple gallon batches it's not going to cool rapidly enough so that you don't have to refill with ice a dozen times. Seems like it's best used for restaurants where they can pop one in and put it in the walk in cooler to decrease their chill time.
Looks neat, but it'd probably take more than 1 to get from boiling to pitching temps - so not great as the only means of cooling. Using it as a paddle to stir an immersion chiller would probably be super effective though.
My restaurant uses these to chill our soups. They are a lot faster than just throwing the batch into our walk in fridge, but would not be fast enough for wort. If they were stainless instead of plastic I could see them working better for brewing.