The "command" is a local command you can run, not a web service to upload keys to. So it's not an attempt to trick people into doing something dangerous (although it might not be a great idea to display private key material on your screen!).
But I'm not convinced that this command will answer the question; if you take the TLS analogy, you can have a client certificate with a 4096-bit RSA key but you can then use that to authenticate to a server with a 768-bit DH parameter! So these parameter sizes are independent.
