A physical crypto marketplace would be pretty cool, or at least some type of public order book. I think having a thread here does not work all that well since it would need bumped often to be relevant.
Pretty much every attempt at a "universal casascius trading thread" hasn't worked.
Seems that you are right on that.
Though mistakes are a must for progress. And some mistakes turn out to be innovation or discovery.
I think that Casascius never intended to make those S2 0.5, but here we are...