Generation X billionaire businessman Ken Griffin says he thinks the “passion is misplaced when it comes to cryptocurrencies”.

Billionaire CEO of American hedge fund Citadel Kenneth Griffin thinks a currency on the Ethereum (ETH) network will replace Bitcoin (BTC) as crypto’s top dog. Citadel manages over $40 billion of capital — a quarter of the trading volume in the US stock market.

During this Wednesday’s Nov. 10 DealBook summit hosted by The New York Times, Griffin said that he anticipates that the “Bitcoin-based conception [will be] replaced by the Ethereum-based conception in the next generation of cryptocurrencies.”

Griffin is a long-time crypto skeptic, especially of Bitcoin — which he claims there are “no commercial use cases for.”

“People are very focused on a world of new ideas and new creation,” he said, “I worry that some of this passion is misplaced when it comes to cryptocurrencies.”

Bitcoin’s annual carbon footprint is around 90.48 tonnes of CO2. Each Bitcoin transaction has the equivalent carbon footprint of 2,008,657 VISA transactions, according to the Bitcoin Energy Consumption Index.

On the flip side, Bitcoin mining also utilizes the lowest cost forms of energy, such as renewable energy and surplus power that would otherwise be wasted. It is also significantly more difficult to actually quantify the amount of emissions that banks and financial institutions are responsible for.

Related: Billionaire Ken Griffin slams crypto as ‘jihadist call’ against the greenback

Earlier this year, there were rumors claiming Citadel was behind the trading limits placed on Robinhood for Gamestock shares. He denied any personal involvement in the saga during the summit, calling it a “bad comedy joke,”