Deep work is more durable, more productive, and more enjoyable.
Deep Work is simultaneously becoming more valuable and more rare, which is a good thing for those who do it. Other people are distracted constantly. Living out of managing the minutia of an inbox, spending all their time either on Facebook or twitter or thinking about those things. The types of tasks that are most durable going into the future of greater and greater levels of automation is the Deep Work kind.
The other, more important reason for WHY: Deep Work brings out real joy and life satisfaction. Deep work is a source of Flow.