System Restore and System Recovery are two different things. System restore is used to restore all changes done to settings or files. This works by scanning the computer memory in case there is any infection or glitch. After the system restore is used, all deleted files cannot be restored, it only works for existing files, and it does this by using the backup option to restore all files on the memory.
System recovery, on the other hand, is an inbuilt feature that enables a user to restore a device to its factory settings. This feature is virtually on all mobile devices and computer. Most times, when you notice, and it seems your phone has started malfunctioning, you can easily make use of the system recovery. This will help in removing malware or infections in your phone and consequently return your phone to the factory state it was when you bought it. All other applications or software that are not inbuilt or programmed with the phone will be deleted.