The SmartScreen Filter prevents users from navigating to and downloading from sites known to host malicious content, including ...

The SmartScreen Filter prevents users from navigating to and downloading from sites known to host malicious content, including Phishing or malicious software attacks.  

If you enable this policy setting, the user is not permitted to navigate to sites identified as unsafe by the SmartScreen Filter.

If you disable this policy setting or do not configure it, the user can ignore SmartScreen Filter warnings and navigate to unsafe sites.