I imagine the second attack may be mitigated by the fact that the publisher might be easier to hide than with direct access. E.g., if your dead man's switch were just some daemon running on a machine somewhere that you have to ping periodically, attackers could find the IP address of the daemon by watching your network traffic.

In the OP, you and the daemon (aka the trusted publisher) communicate exclusively via the blockchain, so it will be a lot more difficult to find the daemon's location.

Not sure if this is in any way better than just accessing the daemon through Tor though.