Vladimir Putin’s finance ministry wants to let cryptocurrencies trade on official Russian exchanges. Kim Jong Un’s hackers are stealing digital cash. Nicolas Maduro hopes a cryptocurrency backed by oil will lure investment back to Venezuela.

All three leaders are wading into the crypto-craze as their regimes grapple with the same problem: Sanctions curbing their access to the global financial system. But while bitcoin and opaque virtual currencies can provide sources of cash for political pariahs, the market’s still too nascent to make a meaningful skirting of a U.S.-led economic blockade possible.

Any autocrat eyeing bitcoin as a sanctions safe haven must confront a simple matter of scale. All the world’s digital tokens are worth about $700 billion, according to Coinmarketcap.com. That’s about one-seventh of the daily foreign exchange market.

“Think about how many U.S. dollars are in circulation and how much each bitcoin would have to be worth to match that value — it would be a ludicrously big number,” said Tom Uren, a visiting fellow at the Australian Strategic Policy Institute’s International Cyber Policy Centre. “In the long term, that’s possible, but we are talking decades and decades. Cash isn’t going away any time soon.”

Curbing the market

Moreover, regulators are quickly moving to rein in digital currencies. China’s central bank declared initial coin offerings illegal in September. And on Thursday, South Korea’s justice minister reiterated a proposal to ban cryptocurrency exchanges altogether. Yonhap New Agency reported Saturday that authorities asked banks to adopt real-name digital currency accounts.

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U.S. Treasury Secretary Steve Mnuchin told the Economic Club of Washington, D.C., on Friday he was “not at all” worried that Russia or others countries could use digital tokens to evade sanctions. “I don’t think that’s a concern,” Mnuchin said, noting that digital coin exchanges were subject to the same requirements as banks to scrutinize who their customers are.

The U.S. sanctions people and organizations, not assets, and those measures still apply to states that park their earnings in cryptocurrencies. Even if Maduro can overcome investor skepticism and attract support to Venezuela’s oil-backed “petro,” those who use the token could find themselves ensnared by sanctions.

“The detail of how you issue it is critical because you have to trust the currency and there has to be a market for it,” said Jim Fitzsimmons, a director at Control Risks in Singapore. “Venezuela is having a really bad time. I just don’t see how the gee-wizzery cryptocurrency stuff is going to help.”