There are many advantages to using a defined advantage strategy. One is that it's easier to allocate resources when you know what your goals are, and another is that you can better communicate with stakeholders when they know how their actions contribute to achieving the goal.
The other advantage is that it's easier to track and measure progress. If you know what success looks like, then you can measure your progress toward it. Having goals helps people stay focused on the task at hand, which would improve productivity. Furthermore, if you have well-defined objectives, then it's much easier to measure your success against them.