Seems to me it's a very niche-y mission (even more so than other non-airliner aircraft). Basically it works if you want to spend a long time up there without actually going anywhere. For sure such missions exist, just not many.
The previous "revolutionizing air transport" effort was German, and spent a couple of years down the road here at Moffett. The racket it made flying over our house all the time (3 x IO540s at 1500 feet, going veeeeery sloooowly) made me investigate it - actually I had a brief chat with the captain (a lady, and a Brit at that) courtesy of Palo Alto tower.
Bottom line is it cruised at 37 knots. It had about the same payload and fuel consumption per hour as a Trislander. Awful the latter may be, but it flies at about 100 knots, so fuel/passenger-mile is about three times better.
For the latest one, they talk about 48 passengers. REALLY??? The German one, which was seriously huge, carried 10, in a tiny underslung cabin.