Slovakia uses EUR though, so maybe it was that. Overall, you can see the trend among the newer EU countries to not adopt EUR, most likely because they are aware it’s essentially the extractive tool, and coincidentally, IMF did it themselves by installing strict monetary neoliberals in those countries after destruction of socialism. Hell even in Poland one of the the strongest voices against the EUR was the infamous balcerowicz.

Anyway, about topic, i don’t think the new currency is intended to replace national currencies, being backed by gold would precluded that, rather it would be nonphysical medium of exchange, and it could also probably function as safeguard for entire block in case of still strong western financiere try to do something funny (financial attack is an old trick by imperialists, going as far as XVIII century).