On the skeleton crew third shift, a critical piece of equipment breaks down. Fortunately, the stockroom has the necessary spare part. The repair tech installs the part, gets the equipment running again, and is off to the next emergency. Production people barely make out his red cape and boots as he leaves the area.
Unfortunately, this tech didn't have access to the inventory system, and there's no attendant on third shift. The stockroom inventory shows this now missing part as being in stock, so it's never reordered. The next time this part is needed, downtime may be painfully extended.
Sure, the tech could have left a note taped up somewhere, written himself a reminder to call it in later, or asked someone to follow up for him. Those aren't dependable methods.
You can solve this problem with a bar code system, RFID tag system, or even a "drop-the-stock tag-in-this-box" system.