As I implied, I find the Haskell-like languages attractive. To the point that I am taking that approach in a toy language.
But you are right, the cost of it is pretty high - not just copy/paste, but it's tricky to parse, auto-formatting is harder, LSP support (changing code) is harder, renaming variables and functions is harder, etc. (Haskell-like languages are worse than Python because they don't always start a new indentation level on a new line, so renaming can change the indentation level.) So it's probably not worth it.
And I will add, like the sibling commenter, I like the auto-format on save of Go. When writing Go, I'll type whatever, often on one line, and let the formatter take care of making it pretty.
It's not just golang, it's your tooling assuming the syntax of the language you use allows it. I do "reformat on a hot key" in both Rust and Typescript, and use it constantly, way before I save, it helps me review and confirm my logic makes sense.
The other advantage is that it standardizes formatting for a given repo making diffs more relevant.
Ironically, I believe Python PEP 8 is what started and normalised the idea of taking formating decisions away from developers.
But you are right, the cost of it is pretty high - not just copy/paste, but it's tricky to parse, auto-formatting is harder, LSP support (changing code) is harder, renaming variables and functions is harder, etc. (Haskell-like languages are worse than Python because they don't always start a new indentation level on a new line, so renaming can change the indentation level.) So it's probably not worth it.
And I will add, like the sibling commenter, I like the auto-format on save of Go. When writing Go, I'll type whatever, often on one line, and let the formatter take care of making it pretty.