Its not so much a problem for the government to be metering out private keys on proof of heartbeat, but rather that it will always want to tie them to an actual identity.

Nobody wants to or has enough trust in telecommunications to present their driver's license in order to participate in an online forum. If DoD really could provide a private key to bypass captcha tests then it could be useful, but there is a zero percent chance that it doesn't get tied back to people with real-world consequences almost immediately.

A persistent, costly ID for online communications and commerce is good and well implemented in an OS like Urbit, but relying on DoD maintaining them is too risky given the current laws around government surveilling, policing, and an ascending domestic 'war on terror'.