Samsung noted that One UI 3.0 comes with enhanced dynamic memory allocation which allows apps to run and perform better, and activities that are running in the background have been restricted in order to provide a better experience and efficient power consumption. Also included are camera software improvements where autofocus and auto exposure are now quicker, and users can now revert edited pictures back to their original versions at any time in Gallery, even after they’re saved.
Security-wise, you can now enable an app to access your microphone, camera, or location just one time. Any permissions that an app has not used in a while will automatically be revoked, and you can no longer give certain apps permission to always see your location in the regular permission pop-up. Should you require an app to access your location for whatever reason, you may do so by enabling it via the location permission page in Settings.