There are various benefits to adding an IR pass filter, including:
The IR pass filter increases the relative strength of the textured IR projector pattern. This enhances the quality of the depth noise and performance range in many robotic environments.
The IR pass filter improves the stereo camera’s depth quality in scenes with repetitive vertical patterns, such as poles in airport, vertical blinds, pipes in ceiling, floor drains or small floor tiles.
The IR pass filter mitigates visible reflections such as overhead lights reflected by shiny floors or tables.
The IR pass filter increases the range performance in indoor no-texture environment such as white-walls.
For further details please refer to Optical Filters for Intel RealSense Depth Cameras D400 and mitigate-repetitive-pattern-effect-stereo-depth-cameras