It is used for multiple purposes which includes scrolling, zooming and selecting.You can use digital brown for watching maps and routes of your location, helps in zooming in or out the location. You can also activate Siri on your mobile and for selecting purposes also with the help of a digital crown on an Apple watch you can select options and icons of the watch.
Read More:- https://cleanersuite.com/how-to-turn-digital-crown-to-unlock-and-eject-water-on-apple-watch/