Yeah, um. I wouldn't exactly list any kind of exercise, low impact or other, as a plus. Not the "always be prepared to go in the water". I actually want the boat so that I DON'T end up in the water. And I'm fully willing to burn fuel in return for effortless movement.
The youtube that scared hell out of me was the one where he...ends up in the water, then climbs back on, only to roll it again. And this is in freaking Australia where I'm pretty sure such things always end up with the person seeing the insides of a great white. In fact, I don't know a single person who has fallen off a kayak in Australian waters that didn't end up eaten by a shark.*
The real appeal to me of a pedal boat is:
1) Very hard to fall out of. So hard that they are widely used as rental craft in places where idiots, drunks, and kids make up the vast bulk of the clientele.
2) No rowing.
3) Well nigh unsinkable in calm water.
4) No rowing.
5) Unlike a kayak, cannot possibly be mistaken for a seal by even the most myopic shark or orca.
6) No rowing.
* I don't know of anyone who has fallen off a kayak anywhere, including Australia. So, technically this is a true statement.