Right but if you delete your entire file system there won't be anything to come along and do the "actual delete" so you're safe until some one comes along with a rescue disk or otherwise mounts it to a system that knows how to deal with this.

At the very least when you rm important-file.txt instead of importanr-file.txt you have a chance.

Pre-delete would already hide files from apps and services for them to "fail fast", and actual delete would be just "i'm running fine for two days". Of course this implies that active open files should not be pre-deleted on unix at all (at least not by rm process). Even if you delete the entire filesystem with backups, there will be a chance to boot into recovery mode and undelete everything back. We can even go further and apply small-file-versioning on fs level to prevent misconfig accidents in /etc.

That's very simple and powerful, I can't tell why it is still not implemented today.