A lot of users including myself run 'go build...' and execute the binary in development. It is recommended by systems file watching services like air.

I think the flag works fine as a solution.

I hate dead code. So many times I've spent two days understanding and maintaining some code and found that one of those days was wasted.

It can be useful at letting you know of things that might be bugs. Like maybe you intended to use x in a calculation but forgot. Or maybe you intended to call func2() but actually called func1() instead. I feel like it should be a warning more than a hard error though.