They're not an Australian exclusive, Europe had them too (minus the UK, I think, I never saw it here, only in France) but I imagine there are going to be a lot of interested collectors. Starswirl is a very sought after G4 pony because of her limited release and the fact she never got to the US.
So yes, definitely worth something. Starswirl has had some insane price hikes at times in the past year or two but giving an exact value is difficult.
The rest of the set was available in the US and other places. It's Starswirl who drives the price and interest up
Nice find to have