The insurance is crafted to cover "force majeure" events that the airline won't cover because it's outside of their control.

Ie, the airline doesn't have direct control over the weather or when their equipment decides to break, but they should (in theory) have control over their staffing levels to provide the service that they marketed and sold.

Flight crew shortage isn't covered by the trip delay policies of any credit card, including the $695 Platinum card.