Measurement gives you transparency and accountability. Those things in turn help you to make game time decisions about what comes next. Without that you will be flying blind making decisions without any real objective data.
We are all prone to subjective biases in our decision-making but the more we can implement objective measurement in the things we do, the clearer our vision will be and there is nothing better for decision-making than being able to see the true state of affairs. Seeing things for what they truly are (based on objective data) is what good decisions are founded on.