Why did we need a new standard for this, exactly? Couldn't we just make password managers pretend that they're a Jubikey or similar? Is it that Jubikeys don't

Why did we need a new standard for this, exactly? Couldn't we just make password managers pretend that they're a Jubikey or similar? Is it that Jubikeys don't offer any extra (master password / biometric) authn, and hence are only suitable as a second factor, where password managers can be used as both?