The builder of this machine apparently couldn't decide between his two hobbies, so he combined them into one mode of transportation. I can't help but think that it is not an easy conversion between the two of them, though.
For a moment, let's focus on the practical efficiency gains contained here. First, we have a motorcycle, which uses far less petroleum than an automobile. The light weight of the vehicle contributes to this, as the engine can be much smaller while still allowing high performance. Also, having two contact patches on the ground increases the efficiency of the vehicle. Next, we have the fishing platform. Read the article, you will find that at 5 mph, roughly walking speed, the vehicle lifts out of the water, greatly reducing contact with the water, increasing vehicle efficiency. There, now we all feel better, don't we?
[Source: Popular Mechanics, via The Kneeslider]