A few legitimate use cases could be:
*Superprotection by stewards of legally or technically sensitive pages, to prevent damage caused by a hijacked admin account. The theory here is that admin accounts are more numerous than steward accounts, so the liklihood of a successful admin account hijack may be higher. Superprotection would proactively limit possible damage. Admins doing routine maintenance work, or taking actions with community consent, could simply make a request for a temporary lift of superprotect by a steward or ask a steward to make an edit themselves.
*Upon community request, superprotection of pages by a steward where those pages are the subject of wheel-warring among local admins.
*Superprotection of a page by a steward for legal reasons at the request of WMF Legal, for example if a page is the subject of a legal dispute and normal full protection is inadequate for some compelling reason.
None of this is an endorsement of WMF's first use of superprotect. I would prefer that if superprotect continues to exist as a tool, that it be in the hands of the stewards and not WMF directly.
Pine