And what do you subdivide it to? How do you trace rays against it? How do you map textures on to it? How do you visualize it in real time? How do you work with it in a different program?
Right, but the rest of the questions remain, along with the usefulness of CSG in real scenarios. CSG can be interesting, but it does end up being very impractical for anything except for some specific effects that are then turned into polygons. It is technically possible to create sdfs and trace against those I'm sure, but csg is rarely used and baking it to sdf instead of polygons even more so.
I didn't say it was impossible, I'm talking about why these other geometry types aren't typically used instead of polygons.
I asked 'how do you trace rays against it' because to do it directly is not fast, yet you are left with all the problems I stated that you skipped over. Think about what it would take to directly trace lots of overlapping primitives. What you gain from tracing it directly is minimal and what you give up is substantial.
Look at the POV-Ray source code. It does it. Again, I am literally telling you how the software under discussion works. and you keep insisting it is not so. It's open source!