FRANKFURT—The European Central Bank needs to issue a digital euro as yielding the space entirely to private sector initiatives like stablecoins could endanger financial stability and weaken the role of the central bank, ECB executive board member Fabio Panetta said. The ECB has been working on designing a digital currency, a direct claim on the central bank much like in the case of cash, but the project could still take around five years before an actual currency could be launched. “Just as the postage stamp lost much of its usefulness with the arrival of the internet and email, so too could cash lose relevance in an economy that is becoming increasingly digital,” Panetta said in a speech on Friday. “If this scenario were to materialise, it would weaken the effectiveness of central bank money as a monetary anchor.” Central bank digital money, while still going through commercial banks, would be …