Essentially, maintenance categories are viewed by the Categorization Project as a particular Project's "personal categories", and as such, the project can determine which ones they use, and how they would like them used on profiles. This is what the Australia Project has done, and we've attempted to outline our approach to profile improvement in the above mentioned page, while keeping in mind, that the minimum sourcing requirement on WikiTree is one source added.
Being a small in numbers Project, the AP wants to avoid the situation where we have maintenance categories with hundreds even thousands of profiles, (Victoria needs Birth has nearly 4,000 profiles, many of which are already in the Unsourced category), and members feeling they need to work on them, when there are other areas to focus their time and attention.
The Unsourced categories will always be the Project's primary maintenance categories, and members will continue to find what sources they are able for those profiles. As the minimum required is one source, we don't want to ask members to spend time chasing records on hundreds and hundreds of already sourced profiles, so many other project related areas to focus on.