Just converts verts to points and vice versa. Materials and Attribute layers are preserved (so for example if you set custom radii on the pointcloud, convert to mesh, then convert back to pointcloud, this will be preserved). Also not add a Radius layer by default (it is still added and filled when adding a pointcloud object from the menu), a global Radius property that will be used if there is no radius attribute can be added later. A Radius attribute can also be added in the pointcloud data properties (and filled via python). This will also add a new utility function that copies materials between datablocks: BKE_id_materials_copy ref T75717 Differential Revision: https://developer.blender.org/D7391