Why is there contact information for the primary care physician?

From TherapyCharts

Research suggests that coordination of care between health care providers increases a patient’s adherence to all treatments. For this reason, we believe that clinicians should be talking with their patients’ primary care physicians, including this contact form as a method of collecting the data necessary to do so. As with any of the features in our site, if you do not collect this information you may leave the form blank and keep it collapsed by selecting the minus button on the form to close it.