In a blog post, Panetta describes crypto investments as a gamble disguised as an investment asset.

"They do not perform any socially or economically useful function," he says. "They are rarely used for payments and do not fund consumption or investment. As a form of investment, unbacked cryptos lack any intrinsic value, too. They are speculative assets."

While other senior payments experts at the European Central Bank have dismissed bitcoin as a marketing scam that will soon burn itself out and should not be legitimised by regulatory intervention, Pentta believes this would be a mistake.

"People have always gambled in many different ways," he says. "And in the digital era, unbacked cryptos are likely to continue to be a vehicle for gambling."

He believes regulation should acknowledge the speculative nature of unbacked cryptos and treat them as gambling activities.

"Vulnerable consumers should be protected through principles similar to those recommended by the European Commission for online gambling," he says. "They should be taxed in accordance with the costs they impose on society."