Not just performance, but static typing and prevalent in the training data/easy for LLMs to reason about.

Of course, your response admits, "second to Rust", which I am guessing is an unspoken question in the grandparent's mind.

Java and C# are there and faster.

If performance is the main difference, whatever that means, then basically Go should be reserved for when Rust and other lower level langs cannot be used due to some other constraint? Are we mainly talking about performant Web backends?

Say I am building some app that I know will be CPU-bound, why choose Go over say... Swift?