I don't understand why so many "style first" bikes omit chainstays, seat tube, or (as in this case) both.
There aren't any extra/unnecessary tubes in a traditional diamond frame. If you leave any of them out, you wind up having to use several times as much material to make a frame that's s everal times easier to break. Why would you want to do that?
This thing is clearly trying to refer back to 1920s motorcycles for style cues. But those bikes looked '20s-cool while having all their structural parts in place. When I see a bike that gets such simple elements of the design so very wrong, it makes me wonder what other subtler design elements they totally screwed up as well.