"Crypto[currency] is a far better way to transfer value than pieces of paper, that's for sure," Musk said on the "FYI — For Your Innovation" podcast.
In particular, Musk said the technology behind bitcoin is "quite brilliant" and "it seems like there is some merit to ethereum and maybe some of the others."
However, Tesla will not be getting involved with digital currency, because Musk says it's not a good use of the company's resources. Plus, creating or mining cryptocurrency takes a lot of computer power, and therefore electricity.
"I think one of the downsides of crypto is that it, computationally, it is like quite energy intensive," Musk said. "It is very energy intensive to create the incremental bitcoin at this point."
Though Musk says he has friends that are "really involved in crypto," in February Musk said he "literally" owns "zero cryptocurrency" other than .25 BTC that someone gave him years ago. (Bitcoin closed trading at $3,924.24 on Tuesday.)
In the tweet, Musk references, @Jack, Twitter co-founder and CEO Jack Dorsey, who is a proponent of bitcoin.
"The world ultimately will have a single currency, the internet will have a single currency. I personally believe that it will be bitcoin," Dorsey told The Times of London in March. It will happen "probably over 10 years, but it could go faster," he said.