Tptacek, whistle blowers level security should not be a use case for this extension , and should be advertised as part of it.
But decreasing the amount of dragnet surveillance by some extent sounds like a good thing to me. For example, many people wouldn't like the government to know mundane stuff about them, like having an abortion.This could help.
* BTW haven't moxie written about an asynchronous diffie hellman key exchange ? it could at least give PFS to this , so the private key would be much less useful ?