In the real world, inventories needs be as complete as possible. In the case of IT assets, it is especially important to retrieve and archive all sorts of model-specific data of hardware components. Specifically, we want the manufacturer, model number, serial number, and if possible, firmware and other hardware specifications. These are useful when dealing with automated administration of warranties.
Typically, the warranties of hardware components are given out according to their serial number. In other cases, it's per manufacturer and model number. This depends on our infrastructure and the retailer suppliers for those IT assets. If we have hundreds of similar pre-made builds, then we might not necessarily care about the individual warranty period of each component. But should we have built the computers ourselves, then we do.
In the case of hard drives, sometimes we also need to know the exact firmware...