Get A Water Car For Extra Roadtrip Options

I saw a Water Car dive into Lake Grapevine, in Texas, a few years ago. I'd never seen such a thing before. In the water that Water Car did not move too fast. The Water Car in the above video is able to keep up with a speed boat speeding on Lake Havasu in Arizona.

I can see where a Water Car would expand ones Roadtrip options. Just drive to Lake Powell and then drive into the lake. No need for a houseboat.

I'm thinking the novelty of a Water Car might quickly wear off. A Water Car is a rather expensive carboat at $200,000. You could get yourself a nice big boat and car for $200,000. Then again you'd save on the expense of renting a marina space, because you could just park your carboat in your garage.

I wonder what sort of mileage the Water Car gets? 20 mph on land? 5 mph at sea?