Stables I rarely discard a silver with it and I have never discarded a gold with it. Just because you have doesn’t mean I will. And so that leaves copper. Besides if you had a copper and a silver in your hand it’s not like your going to choose to discard the silver over the copper anyways. No because that would be foolish. Which proves my point stables is better off as a copper strategy. Simply because it’s the better treasure to discard.
Copper is the better treasure to discard there, yes, but not because it's any better intrinsically in that role - all treasures are equal there - but because it's really bad in any other role.
(This is also, incidentally, the reason a lot of local club chess is played on weekday evenings. It's not that weekday evenings are especially well-suited to local club chess, rather that they're really bad for any other form of competitive OTB chess.)