I think one of the purposes of the test was to ensure that the crew can escape safely from a dramatic fireball. It's hard to simulate throwing shrapnel and fuel

I think one of the purposes of the test was to ensure that the crew can escape safely from a dramatic fireball. It's hard to simulate throwing shrapnel and fuel at the Dragon capsule without actually blowing up the booster. However, the Falcon wasn't intentionally detonated! This was also by design; if explosive charges were placed down the side and made it come apart naturally, it would come apart in a predictable way. If you know anything about test-driven development, someone would try to made assumptions about the explosion. By allowing an uncontrolled explosion at the time when the Falcon is experiencing the most extreme aerodynamic forces, it's basically creating a worst-case scenario. SpaceX successfully proved that the Dragon capsule can escape from that worst-case, and that's great news. It'll be flying with crew very soon, I think.