They are stacked, but mostly for the novelty rather than investment. They go down well at the coin club because they are large, crown sized rounds with big easy to see designs. The most popular ones are the "Bitcoins". They usually sell for around $5 with no issues but people only really want one, they don't want a whole tube. They will buy a few if they all have different designs on them.
I bought a few that were part of a monetary program from a US group who were trying to introduce a Gold: Silver: Copper currency standard, American Open Currency Standard (AOCS). It has yet to take off but when it does...
I still have my copper bar and round and a tube of the AOCS along with some copper Liberty Dollars "Ron Paul for President 2008". They have more historical interest than investment purposes.
Copper tones really quickly, takes fingerprints easily and leaves your hands smelling if you handle them too much, I prefer silver if I am going to fiddle a round.