You probably wouldn't be committing this, unless you're backing up a heavily WIP branch. The issue is that if you're developing locally and need to make a temporary change, you might comment something out, which then requires commenting another now-unused variable, which then requires commenting out yet another variable, and so on. Go isn't helping you here, it's wasting your time for no good reason. Just emit a warning and allow CI to be configured to reject warnings.

I will need it two minutes tops. If I don't use it by then, I'll delete it, especially if it gives a warning like Rust does. But this? It just gets in the way.

Have you looked at the post? Use case: you are testing something or playing around and you want to try something. That's supper common

I have a use case in Powershell: my company has a number of scripts that are minimally but importantly customized per-location, and I have an otherwise unused "SiteId" variable where I keep the location name for that specific script for a quick sanity check when I'm looking them over for any reason. Not necessary, but useful to me. Probably wouldn't do the same thing in a compiled program, but I can at least see where someone might want something similar.