You are able to, as an (administrative) manager, use the Inventory for not only Articles but also other items. For example: vans, detectors or drilling machines.
If you assign the materials to a user you are able to know exactly which materials a user has. But the overview itself is not the only reason to assign detectors or pressure meters to a user. By linking them it will be easier to register leakage tests or pressure tests as the device information will be autocompleted.
Do your technician a favour and register all their materials in the Inventory.