It’s faster than Node or Python, with a better type system than either. It’s got a much easier learning curve than Rust. It has a good stdlib and tooling. Simple syntax with usually only one way to do things. Error handling has its problems but I still prefer it over Node, where a catch clause might receive just about anything as an “error”.
Am I missing a language that does this too or more? I’m not a Go fanatic at all, mostly written Node for backends in my career, but I’ve been exploring Go lately.
Given Python's substantial improvements recently, I would put it far ahead of the structural typing done in Go, personally.
Go (and lots of other languages...) wreck it on dependency management and deployment, though. :-/ As the saying goes, "it was easier to invent Docker than fix Python's tooling".
I didn't really use it much until the last few years. It was limited and annoyiongly verbose. Now it's great, you don't even have to do things like explicitly notate covariant/contravariant types, and a lot of what used to be clumsy annotation with imports from typing is now just specified with normal Python.
And best of all, more and more libraries are viewing type support as a huge priority, so there's usually no more having to download type mocks and annotation packages and worry about keeping them in sync. There are some libraries that do annoying things like adding " | None" after all their return types to allow themselves to be sloppy, but at least they are sort of calling out to you that they could be sloppy instead of letting it surprise you.
It's now good and easy enough that it saves me time to use type annotations even for small scripts, as the time it saves from quickly catching typos or messing up a return type.
Like you said, Pydantic is often the magic that makes it really useful. It is just easy enough and adds enough value that it's worth not lugging around data in dicts or tuples.
My main gripe with Go's typing has always been that I think the structural typing of its interfaces is convenient but really it's convenient in the same way that duck typing is. In the same way that a hunter with a duck call is the same as a duck with duck typing, a F16 and a VCR are both things that have an ejection feature.