Hi Matadem, you can't show points on a solid where the "underlying surfaces" are not made up of the same points where they have a joined edge.

There is some additional description of this on the FAQ here:
https://moi3d.com/faq#Q:_Why_does_show_points_work_for_some_objects_but_not_others.3F

If you use Edit > Separate to break your object into individual surfaces you should then be able to show points on the separate surfaces.

- Michael