Honestly, Iranian banks have a better chance of wiring money abroad if they use Monero, but obviously it's not a solution the government will accept, because well, no control. If they decide to fork any existing cryptocurrency or create some kind of token, it's likely to be banned on exchanges. I don't see how they could pull this off.
The big problem for any existing system is volume: Iran has enough money that they’d dominate the real currency exchanges and once that happens the risks go up for everyone involved. Even the most ideologically committed cryptocurrency proponents are going to think twice about going to jail on behalf of a foreign power without compensation.
Monero used to traded for around 45 cents ($0.45) for about 2 years, it trades for $45 right now, your argument would have worked A LOT better then. Why is Monero $45 right now? For the obligatory devil's advocate response who will you blame: dark net markets, sanctioned countries, better user experience? All we have are correlations and these networks are working as intended, and have gotten a lot more hardened and resilient. So let it trade for $4,500 just because Iran has some money to move.