Supply chain management is about vision more than electrons.
Some capitalist world transactions seem almost as inane from a certain perspective. A typical supply house purchase might originate with an outside salesperson, who calls it in to an inside counterpart, who relays the order to a warehouse picker, who conveys the goods to a shipping clerk, who passes them on to a truck driver. Even more parties come into play if the order includes items not in stock. At least five and maybe more individuals have to do their jobs right in order for the customer to get what he wants in timely fashion. Even when that happens, all those handlers increase the odds of mistakes cropping up on the invoice or with inventory subtraction or some other recordkeeping. When you think of all the opportunities for supply mismanagement, it's a wonder any order gets handled without a glitch.