The thing is, you still need to validate the session id, if you want to know who you are talking to. And in order to do that, you probably need to do something

The thing is, you still need to validate the session id, if you want to know who you are talking to. And in order to do that, you probably need to do something like use x509 certs. And once you do that, you've basically re-arrived at the same layering issues that TLS has. So, like, the protection against passive listeners is nice. But, what I don't understand is a specific example of where using tcpcrypt would be better than just using a widely used TLS library.