Do you think silver would play a role for even smaller values or will physical transactions just take place at these higher values? I'm not informed enough to say. It's most definitely possible. I'm not even certain if gold cash will pan out, just that it's a distinct possibility. However, given the historical relationship of gold and silver, smaller silver denominations is entirely possible. It's only downside would the the fact that silver and gold sometimes drift from each other in value, which makes running a monetary system with both very difficult.