I have always found this business of "copper smells" interesting, since copper being a metal, it could not be vaporizing to any real extent and affecting our noses. I suspected something like the following, which makes good sense:
https://www.nature.com/news/2006/061023 ... 023-7.html
In any case there is certainly a smell, but it is not the copper you are smelling, but compounds from your own body that are generated by contact with copper. They don't call it catalysis, but is sort of sounds like that to me, it isn't clear (to me) if the compounds themselves actually contain any copper.
It is hard to imagine this would be significant from something as small as the Manix ball cage.