Iran has been under export controls for dual use technology for decades. Getting the amount of GPUs needed to conduct bitcoin mining was nigh impossible.

Bitcoin and Crypto as a shadow financial system was enabled by Qatar and the UAE where there are dedicated deal desks that work on ExAmerica trades.

This is why the IRGC striking Qatar and the UAE was such a bad move. Even companies in the PRC try to follow American sanctions regimes because trade with Japan+SK+ASEAN is higher priority than trade with Russia or Iran.