Not sure I'd use it in the canadian shield.  Potentially, those plastic fins would not retrieve well from a pile of boulders and if they did, they would quickly break.  Gimmick if you ask me but I like the way the guy is thinking.  You would achieve the the same with any lightweight sack so I see only a disadvantage in the product for where my canoe goes.  Otherwise, if you paddle in a soft bottom lake . . . knock yourself out.

Personal opinion:  Anchors are a bad idea in a canoe or kayak anyway.