They're right not to be. Vortices will kill the air flow into the engines.
Delta fly with alpha. This is not a delta. It has a sharp nose with flat size. You don't know what could be the attitude of the fuselage in flight.
And, once again, IMOHO, this is more a "flying boat" (understand a boat flying) with a fluid flow slightly more dense than air (hence less vorticity). Given the discussion around the non moving nose wheel and rudders in turn on the ground, this "air"-frame can even be a towed model/glider.