I don't see the usefulness. You can sign a lie cryptographically just as well as a fact.
The government isn't allowed to force you to lie; they can force you to be silent. By updating this regularly it then becomes apparent when you have been forced into silence.
You can find these specific requirements for secrecy onerous and undemocratic, and I might even agree with you. But these "I'm not really violating the law" posts by non-lawyer geeks are boring. There are all sorts of reasons society can demand you not to make certain communications. If you stop communicating to make the communication, you are still doing the communication in violation of the law.