This helps not only us but submitters for a number of reasons:
- Submitters often forget to include part of their code (custom objects, Apex classes, etc.) and using an unmanaged often catches most of the dependencies.
- Allows reviewers to be able to easily install submissions if they don't have ANT installed or are not familiar with ANT. Some reviewers may look at functional instead of technical aspects of the submission.
- Allows us to easily uninstall the code so that we can reuse an org for multiple submissions.