I'm a stacker, not a collector. I have hundreds of Perth Roo coins in my stack, not because I like the design on the face or the collectability, it was because they had the cheapest premium on any 1oz piece of Perth Ag. When the economy falls over and the metals head for the stars I need smaller denominations to sell/trade for smaller items (like a new car). I can't make smaller purchases with my 100oz bars, hence the need for coins.
At the end of the day, silver is silver and when it's in high demand, nobody will give a shit if it's a Kookaburra, Roo, Rooster etc. They will want it for the Ag valve, not the collectable value.