"Bitcoin as a digital currency is not quite there yet," Jerry Yang, who now heads AME Cloud Ventures, told CNBC on Thursday.
"Personally, I am a believer in how digital currency can play a role in our society… but for now, it seems like it's more driven by the hype of investing and getting a return rather than using it as a transaction currency," he said, while speaking on the sidelines of the Fortune Global Forum in Guangzhou, China.
On Thursday, bitcoin accelerated past the psychologically key level of $15,000. The landmark happened on the Coinbase exchange at 10 a.m. London time (5 a.m. ET), trading as high as $15,200 on that platform.
The digital currency began the year below $1,000 but gains have skyrocketed in recent months as investor interest grows. Bitcoin's dramatic uptick in market value means it would currently rank among the 20 largest stocks in the S&P 500 — with an estimated value of more than $250 billion.
However, while Yang suggested he was a "believer" in the digital currency, many others remain skeptical.
JPMorgan Chase CEO Jamie Dimon said bitcoin is a "fraud" that will eventually "blow up." Elsewhere, digital currency investor and former Fortress hedge fund manager Michael Novogratz said last week that cryptocurrencies like bitcoin were "going to be the biggest bubble of our lifetimes."
Novogratz also predicted that bitcoin could reach $40,000 by the end of next year.
—CNBC's Evelyn Chang contributed to this report.