It instantly splits the mesh into separate Polygroups along that curve. Use Knife Curve to physically delete geometry along the line.
The 0.8 update fine-tuned the radial symmetry count beyond 10. Artists creating mandalas, wheels, or intricate sci-fi panels reported that the previous version lagged when using 20+ symmetry axes. 2022.0.8 optimized the draw calls, making radial work smooth even at 100+ axes. zbrush 2022.0.8