I guess there are advantages to that and according to google: "..this airplane was a beautiful example of excellent supersonic aerodynamics.

It sported a slender and streamlined fuselage with a pointed nose, and a very thin short, stubby wing with a leading edge as sharp as a razor blade – all designed to reduce supersonic wave drag on the airplane.

A wedge shape was used because it is more effective than the conventional tail as a stabilizing surface at hypersonic speeds."