Is SOA about reusability or agility?

David Chappell talks about SOA and reusability as if they relate to each other. I can somewhat agree , but from my point of view reuse isn't the main benefit of SOA. I would say agility is the main benefit and the foremost design goal for SOA.

Comparing reusability and agility in terms of which one is the easiest to achive, reusability is by far the harder challenge. Impediments to effective reuse are deeply rooted in human nature. Agility on the other hand is not.

While reusability belongs to object orientation, agility is the goal with service orientation and achieved with loose coupling between services in a SOA. David is mentioning service orchestration as the way of reaching loose coupling, but doesn't that relate to process management? I recently posted a few rows about the aspects of loosely coupling when it comes to service management and process management. I would say that agility can come from either, but a distinction between SOA and BPM need to be discussed.