Welcome to Tiny Homes, an idea that is more popular with minimalists than with neighborhood associations and zoning boards. We'll point out the fun parts. Usually you'll have to check out the logistics and legalities. This one floats, so that makes it all good.
Barge boats make no claims to speed. Their hulls are beveled boxes, not streamlined sculptures. One advantage houseboats have over tiny houses on wheels is length and width. Longer and wider are better for boats, but not for houses that have to be towed down the road.
This boat is
listed, oops, bad term for a boat...its asking price is $185,000 for a 36 square foot boat. That works out to $5,139/sq. ft. It must be luxurious. It must also be very narrow because the unit is also 36 feet long. That means it must be only one foot wide. There appears to be sufficient reason to assume some error in the listing, oops, house description.
Besides the Lake Union waterfront, what else do you get? Water below. Water beside. And, because this is Seattle, frequently water above. You don't get a lawn. Yay! You probably get gulls and geese. And what they leave. Yuck. You also get a place to put in your kayak for your commute. Very nice.
The boat is called a unit because it is part of a condo arrangement. The list of amenities includes the laundry, which is good. Off-street parking makes sense. No garage, of course. The rest of the neighborhood seems to have the privacy necessities that keep tourists from walking your dock and curiously peeking in your windows.
Peeking in the windows might be necessary if you're going to make an offer, though. The photos are all of the exterior. It has a fun paint job, enough room for a small container garden, room for some chairs, kayak storage, plenty of windows, and what looks like a dutch door.