Only physical buttons are used to interact with the app during the run.
Use the app to keep track of your pace and correct the distance during a race according to the km markers if the GPS is obviously wrong. Your pace planning is adjusted to the corrected distance.
Works with Strava. Tracks heart rate and step count.

Once the app is ready to record, all interaction is exclusively with the crown. Start the run with the crown, adjust your distance according to the km markers or other known landmarks (i.e. laps on the track) also with the crown. Mark the end of the run by pressing both buttons at the same time.

Crown Run (iOS) also shows your distance of the last 30 days as a graph with the option to toggle to intensity in order to make smart choices about your training. Plan out your training according to intensity estimations to ensure you are not overtraining.

Also please note that continued use of GPS running in the background can dramatically decrease battery life.

Crown Run reads and shows you the following data from the Health app (HealthKit):
Heart Rate
Step Count