I’d assume they care because Go was designed to keep the codebase as “neat” and clean as possible when being worked on by many developers. Given enough time and developers, things like unused variables will start to seep in and make the codebase dirtier.
Of course if you’re the only developer working on your own codebase, you’d wonder why they care but you’re also not the main group they were targeting.
Of course if you’re the only developer working on your own codebase, you’d wonder why they care but you’re also not the main group they were targeting.