Apple co-founder Steve Wozniak said governments won't ever give up control over cryptocurrencies.

He said cryptocurrencies can be used effectively in payments, and shared why he likes bitcoin.

"Bitcoin is mathematics, mathematical purity. There can never be another bitcoin created," he said.

Steve Wozniak is one of many tech personalities who like cryptocurrencies, but believes they won't ever be free of government control.

The tech entrepreneur, who cofounded Apple in 1976 with Steve Jobs, praised Twitter boss and crypto enthusiast Jack Dorsey for triggering conversations on how cryptocurrencies should be at "the heart of our business dealings."

"Trouble is, the government will never allow it to be out of their control," he told Yahoo Finance in an interview on Friday.

"If it got to the point that everything was being done with crypto, and it didn't pass through governments for observation and taxation and all that, now governments would just disallow it. They wouldn't give up their power."

But Wozniak thinks digital currencies will develop into a functional method of payment. "I'm in that camp that crypto will be used effectively," he said.

"We have so many digital ways to pay for things now, even just to transfer money to people. It goes way back to PayPal," he said. "We have Apple Pay, Apple Cash, Venmo, and all that. So we already have other modes than crypto."

Still, he isn't sure whether the surface anonymity of cryptocurrencies, compared with other forms of digital payment - in that it is more difficult to identify and track holders - is a good thing.

"Crypto just has a little bit of anonymity. And I don't know if that's right, that 'Oh, gosh, I can do things without people knowing.'"

But crypto anonymity is a big misconception, CoinFlip CEO Ben Weiss has argued. He noted that people cannot buy cryptocurrencies without going through "know your customer" checks and providing some form of identification.

Gary Gensler, the chairman of the Securities and Exchange Commission, has been calling for more oversight of the crypto industry. He has said the digital assets can only become mainstream if clear rules are in place to govern the industry.

Wozniak explained that he likes bitcoin because its supply is capped. "Look at the US dollar - the government can just create new dollars and borrow; it's like you never have it fixed, like bitcoin," he said.

"Bitcoin is mathematics, mathematical purity. There can never be another bitcoin created."

Beyond digital money, Wozniak praised the promise of blockchains and their potential use cases - including, perhaps, in voting in political elections.

"Crypto has an awful lot of promise through the blockchain of different things it can do differently than before ... right down to elections even," he said. "It has a very trustable format that can't be modified easily."