Since the center points of the cantons can be calculated from the present data, it is not necessary to add them to OSM.
They were removed in https://www.openstreetmap.org/changeset/173255219
If (and only if) there's a physical feature present at the center point of a canton or municipality, then this can be mapped of course.
I did so in https://www.openstreetmap.org/node/7616510930/history/1