The main idea seems to be that it would be hard to "undeploy" a properly designed C2 server in form of a smart contract on Ethereum. While that is true, the authors don't add something new to the discussion: in their opinion the open nature of Ethereum is simply a "design flaw" and smart contracts need "authoritative control".

The discussions around the OFAC sanctions showed that world isn't that simple. Who would decide about "malicious" users and use cases?