Your points are great but SSH is extensible so openid connect support doesn't mean much since you can do it with existing ssh.
"Security by obscurity" is only a thing if you're relying on that mechanism for security. People already configure SSH port knocking as you noted. It can be considered attack surface reduction and is a good feature given they're not using a secret link for any security control.
One benefit of their approach might be how you can use TLS pki now instead if setting up ssh-ca's. Potentially you would need to manage less pki.
But a criticism I have is how http* has much more vulns and new attack techniques being developed all the time unlike ssh. I can imagine LFI or request smuggling on the same http/2 web server causing RCE via their protocol.
"Security by obscurity" is only a thing if you're relying on that mechanism for security. People already configure SSH port knocking as you noted. It can be considered attack surface reduction and is a good feature given they're not using a secret link for any security control.
One benefit of their approach might be how you can use TLS pki now instead if setting up ssh-ca's. Potentially you would need to manage less pki.
But a criticism I have is how http* has much more vulns and new attack techniques being developed all the time unlike ssh. I can imagine LFI or request smuggling on the same http/2 web server causing RCE via their protocol.