I doubt this vehicle will be used for landing on Earth(why not use parachutes?). I would rather send it to Mars orbit and reuse it there as a landing module, but not take it back to Earth.
Why not use chutes? Because with rockets, you can steer, and fine-tune the rate of descent. You don't need to splash down at sea, you can land on solid ground, and pick which bit of ground to land on (such as a spaceport). It's less of a bumpy ride and cheaper to recover.
The auxiliary solid fuel rockets of the space shuttle slashed in the sea with parachutes and were "reusable". But they were so bumped that the refurbishment procedure involved a lot of handwork and iirc more than a month.
