Context here for those who don't know: SpaceX' declared goal is to put humans on Mars. Mars has enough atmosphere to cause trouble (burning up in free fall), bu

Context here for those who don't know: SpaceX' declared goal is to put humans on Mars. Mars has enough atmosphere to cause trouble (burning up in free fall), but too little for any kind of coming to a stop with parachutes. Cf. how Curiosity landed, which wouldn't have been necessary on Earth. In any case, SpaceX doesn't like to be constrained by things that only work on Earth, and while parachutes were considered for recovering the first stage they found it wouldn't really work (and dropping things into the ocean tends to not do them good). So propulsive landing (despite sounding more complicated) is actually a better option than others here.