HUF was formerly supported but then put on the legacy bin, likely due to the European Union demanding equal treatment to all customers by permitting regional prices within the EU if ALL EU members had access to them. Therefore, a single EU price for everyone, and the highest one for maximized profits.

The only exception is Poland, because Poland, by national law, requires payment in PLN if goods were sold in Poland, putting Valve into a catch-22 position because the payment system does not support multiple currencies for one Store region nor does it support real-time conversion of prices from EUR to PLN. And yes, only Polish people have access to PLN pricing (and in turn no access to EUR pricing) which is in violation of EU law.