I think Go's unique selling point is: it's the anti-LISP, the programming language that isn't particularly programmable and you don't miss it, because the built-ins are sufficient. As a result, code in Go tends to be far more about solving the problem than is the norm; in most languages, you'd first be solving the language or replacing the stdlib. Concurrency is an example, yes, but so are the HTTP and the TLS libraries.