Disclaimer: PLY Simplify is not intended as an All-in-one PLY support system. It is merely a tool to help visualize, and view colored ply data for certain applications. This node setup is meant for use of point cloud data using Blender's Native system which uses vertices. Heavy Point clouds can still bog down the system, therefore be sure to simplify. I found this necessary and helpful and I hope you do as well. 

If the point cloud is not set to colorize it will use blender's native instance points from geometry nodes and is therefore very quick, but will not render. I have personally used point cloud data to build a 3D model of a space that had well over 150 million points and there was no lag whatsoever when navigating. However, there was no color information needed as I was merely using the point cloud info the build the walls, ceiling and other fixtures present in the room.

I have used this geometry nodes setup to help model different 3D spaces, such as NBA arena's, and clubs and it has been very useful in combination with CAD's to verify and build out internal spaces. 

Colorizing the point cloud will put geometry at every vertex in the point cloud. Currently PLY Simplify's LOD 1 places a 4 sided pyramid at each point effectively multiplying the point clouds vertex count by 4. If you have a point cloud with 25 million vertices and attempt to colorize it, without simplifying, you are effectively trying to visualize 100 million vertices which can be very heavy depending on your computer's specifications. This may crash your system. Please beware.