Mars Lander

NASA is planning to deploy the next Mars lander with a sky (if you can call it that on Mars) crane.

First, isn't it great that NASA is hiring video game cut-scene designers to create these videos? Changes in focus, camera shake, and variable angle are a lot more likely to elicit "ooh"s and "ahh"s than the old "track the object as it comes closer to the camera" view we got in the early 90s.

Second, um, why do we need a sky crane? The last one, if you recall, hit Mars using a pyramid shaped set of inflatable orbs. It then opened and the rover rolled off. That, in my mind, left a lot less room for error. No rockets to fail, and if one of the bubbles didn't inflate, the rest would still be there to protect the vehicle. Here, if one of the retro rockets or one of the girdles, or the umbilical were to fail, the rover would topple down to the planet with no protection.

Can anyone (who actually knows about space science - not someone who is happy to surmise, as I am) explain it to me?