The POINTCLOUD command was designed to work this way. In ARCHICAD, GDL objects created by the PointCloud add-on contain exactly one PointCloud reference per object. This is why names as variables are not accepted in the first place. The second reason for this was to support background compatibility, same as with macro calls: exact names can be handled deterministically, which makes it a lot faster to process.
Objects created without the add-on can contain more POINTCLOUD commands.
POINTCLOUD command is more like a macro CALL without parameters than a PICTURE.
Library Developer, Library Team