Screen blurring is helpful if you don't want sensitive information to display while switching between multiple apps open on your iOS device. Disabling a third party keyboard prohibits a user from using another keyboard when typing texts which can expose your device to security risks.
Note: The screen blurring feature will only be visible if you have several apps open. For iOS and iPad 14.5 OS and later, settings will take effect immediately. For older versions, try restarting or relaunching the app if the settings didn’t load.