One advantage is that you avoid having to jettison the escape tower which would add some complexity and risk. Also, the engines are designed for use in space d

One advantage is that you avoid having to jettison the escape tower which would add some complexity and risk. Also, the engines are designed for use in space during a normal mission and to be recovered. So in that configuration the crew would still need to be located close to a hydrazine thruster as a part of a normal flight.