I've had many short lived 'Paddle Trails', here's a couple....
Iowa. Difficult to say if the ozcut sharpener is the same. The angle looks steeper to me. Regardless, they seem to be offering only one block of a single grit. You would still need to work down the tip with a file before going to the block, and depending on the coarseness of the grit, it could take quite a while to true the entire bevel. Looks like it's made more for touching up heads.
Terry Green swears by them. I may have seen one of those bloodtrails.