"No matter what anyone thinks about it, government is going to regulate it. They are going to regulate it for (anti-money laundering) purposes, for (Bank Secrecy Act) purposes, for tax," Dimon said, referring to banking regulations in a conversation held virtually by the Institute of International Finance.
Dimon, head of the largest U.S. bank, has been a vocal critic of the digital currency, once calling it a fraud and then later saying he regretted the statement.
This summer, JPMorgan gave wealth management clients access to cryptocurrency funds, meaning the bank's financial advisers can accept buy and sell orders from clients for five cryptocurrency products.
Stating that his views are different from those of the bank and its board, Dimon said he remains skeptical.
"I personally think that bitcoin is worthless," Dimon said. "I don't think you should smoke cigarettes either."
"Our clients are adults. They disagree. If they want to have access to buy or sell bitcoin - we can't custody it - but we can give them legitimate, as clean as possible access."
Bitcoin trading showed no immediate reaction to Dimon's comments. The cryptocurrency was last up 5% for the day at $57,304.
(Reporting by Elizabeth Dilts Marshall and David Henry; Editing by Steve Orlofsky)