In 2017, Thomas Peterffy posted a full-page ad in the Wall Street Journal warning of the dangers Bitcoin futures pose to capital markets.

But these days, he has become well-versed in cryptocurrencies, saying it is prudent to have 2% to 3% of personal wealth in crypto in case fiat crashes.

"I think it can go to zero, and I think it can go to a million dollars," Peterffy said in an interview. "I have no idea," he noted.

That is one great example of changing attitudes towards cryptocurrency, from investors who once despised or feared digital tokens but realized, especially in 2021, that they couldn't pass up a big profit opportunity.

Bridgewater Associates founder Ray Dalio also revealed recently that he has at least some Bitcoin and Ethereum in his portfolio, months after he questioned the usefulness of cryptocurrency as a store of value. Dalio views investment as an alternative money in a world where "cash is trash" and inflation erodes purchasing power.

Meanwhile, Paul Tudor Jones revealed that he invested as a hedge against inflation.

A recent survey of banks also indicated that almost half of family offices were interested in adding digital currencies to their portfolios.

This shows that crypto has become more mainstream, albeit with varying degrees of success.

Crypto enthusiasts are still hoping that US regulators will approve an ETF that will actually hold bitcoins in 2022.

Galaxy Digital CEO Michael Novogratz said in December 2021 that prices could move sideways in the short term, but Bitcoin will not fall below the $ 42,000 low. "So much money is pouring into this space," he said. "It would make no sense if crypto prices would go much below that," he added.