I mentioned this in another comment, but I once had a bug with a build caused by a JAR file (which is just a zip archive) ordering the files differently inside the zip archive. I'm not sure if it would handle that particular case, but more commonly you might have a huge build directory and want to see what files are different (particularly on Windows where you can have dozens of different DLLs).

This saved a lot of effort verifying artifacts when my team ported a large codebase from maven+cmake to bazel. It's very good when you're doing build changes, large scale refactors, or partial rewrites.

Beyond build engineering, I've also found it useful to debug container image differences.