your thought process makes sense looking at the problem through the eyes of someone used to mass production and cheap materials. these were made during a time

your thought process makes sense looking at the problem through the eyes of someone used to mass production and cheap materials. these were made during a time that the expertise to create plus the material itself was expensive, and these have been found in a wide area so not some incredibly niche item. tools of questionable use would quickly fall from use and not spread beyond the first few creations, toys or trinkets would likely not be made of metal nor stored with other valuables like coins etc. this doesn't mean it is of military or religious significance but I do think this is more than a toy. The fact that it seems to be geographically locked (thus culturally locked) leads me to think this is a cultural item or something that was more useful for that geography - there have been those who have linked it to a calendar. This makes sense given the geometry of the item (12 months [sides], 30days [edges]) and in the northern area's it would be of greater need to time crops - especially for feeding large armies from Rome. The idea of expensive toys / fads can definitely have it's place in very small numbers and incredibly narrow regions, beyond that I think you have to look for more useful needs.