As a user, it would be cool if I could navigate to settings, enable Beta features, and immediately see and interact with the individual beta features.
The user taps the menu and selects Settings, enables Beta features and must now tap save. At this point, the user can return to settings and interact with the beta features.
When the user enables Beta features, the features are immediately displayed, and the user can interact with them. Tapping save would confirm enabling beta features and set the applicable features as well.