There are all sorts of arbitrage and correlation trades to be made in bonds, stocks and similar securities (mortgages) because they all have intrinsic values or maturity dates, etc. To protect the banks capital it’s important to restrict the types of trades allowed, and to disallow pure speculation.

Jamie in that article describes cryptocurrencies as pure speculation because they have no intrinsic value, which is why he said he’d never allow employees to trade them.

But one thing I believe about Jamie Dimon is that he has a sharp and flexible mind. If the newer innovations in the DeFi markets around crypto convince him he’s wrong about cryptocurrencies, he will turn on a dime. While still putting in adequate safeguards for his banks capital.