Good luck selling your rounds. I remember in the mid 90s when I first enquired (but never brought) about gold, the dealer said that they ONLY buy back their own brand of gold. Wow... Lots of modern dealers are also similarly discriminating when buying back.
Why not conduct an experiment and try and sell your rounds to various bullion dealers? It might be enlightening.
Junk silver is even worse... an important points made by Robert Mish (in his interview with Chris Martenson) was that in the late 70s, junk silver sold for up to 30% less than spot price, due to the refinery back-log.
So when the heights of the market are again reached in the future, you can either sell your junk silver to a bullion dealer for a 30% discount, or you can sell it here for spot price, where it will be juggled between different SS like a hot potato, because no-one wants to be the sucker who has to sell it to a dealer and lose 30%. Probably silver rounds can be juggled like hot potatoes too?