So once again I got a contribution rejected  only because I have left a unused use statement. This sort of reviews are mostly useless and are a waste of time for both the reviewer ad the contributor.
The reviewer should be focused on finding bugs, security issues or design flaws in the architecture (or anything that increase the code quality) not on things that have no impact (or so small it's hardly measurable) at the execution and that can not become an issue in the long term maintenance of the software.
This request is introduce a sniff to catch the unused use statements early in the dev process and autofix them.
This was already attempted in request #13068
but due to a bug in the sniff, it was reverted. The bug has been fixed but a release of slevomat/coding-standard has not yet been released with it. In the meantime I'm just going to pull the fixed sniff in our sources.