The incredible range and precision paired with a reddot optic makes the SSX-23 a deadly precision gun. The reddot does not cover half of your target like the fiber optic sights do. Also you cannot make any alignment mistakes which will make your shots more precise especially at long ranges.
Backup fiber optic sights
The slot in the sliderail allows you to use your fiber optic sights even with the rail attached. This can come in handy when your Reddot runs out of battery.