Doctors and researchers at the University of Washington with Microsoft volunteers have built a tool to alert you about highly relevant public health announcements, potential exposure to COVID-19, and to assist public health officials and contact tracing teams without compromising your personal privacy.
It would be really useful to show usage statistics like how many people globally or locally are using the app.
Displaying these statistics in some visual or textual form will help immensely in conveying credibility and legitimacy of the app.
Otherwise the user could simply think no one else is using it and delete the app afterwards.
More details forthcoming on the requirements for this.