Chiefly, Go sacrifices expressiveness for uniformity.
The general principle is to favour the transparent and ready-to-hand over the remote and opaque, the concrete and literal over the abstract and magical. It’s like speaking a language without metaphors.
Learning Go won’t teach you any exciting new computer science concepts, or introduce you to a whole new paradigm of software development (for that, try Idris). But it will give you a better understanding of the breadth and variety of the design space for programming languages, at a time when mainstream languages generally seem to be converging (Kotlin is rather like Swift, is rather like Typescript, etc). Sometimes it isn’t the innovative new features that distinguish a language, but its choice of restrictions.