Remember that with reusability in play, the guidance system can decide "screw the first stage landing, the payload is more important" and simply switch to an expendable launch profile if it turns out that you have more engine problems on the first stage than you designed for. Then you use the reserve fuel to get the $300M satellite safely to orbit instead of getting the $30M stage safely to the ground. The customer is happy and you've only lost a unit for which you have a dozen of direct substitutes in storage anyway (SpaceX already doesn't have enough storage space, apparently!).