Before appearing in the Google Play store, every app undergoes Google's security screening process which includes identifying malware and ensuring that apps conform to Google's policies. Play Protect continues that process by scanning billions of apps daily to make sure they remain safe and in compliance.
Play Protect's appearance in the Google Play app is Google's way of bringing their existing screening process to the foreground of your experience. Using the new Play Store, you will see when your apps were last scanned. Google says it works around the clock, constantly updating to keep up with the latest threats. Play Protect goes hand in hand with the other-deceptive-ads/">safe browsing feature
Google clearly wants its users to feel safe in knowing that it has an automatic process in place not only in the background but on your device as well. For all the details, follow the source links bellow.