Suppose that you run a warehouse in which different forklift crews store incoming items and retrieve outgoing ones. If you run a busy operation, your forklift operators might need help finding items on shelves. If you tie the forklifts into your computer systems with a wireless LAN, the operators can both tell the computers where new material has been stored and find out from the computers where to go to fill an order.
Or, suppose that your offices are in a building with lath-and-plastercovered cinderblock walls. Drilling through the walls and setting boxes for LAN connections could be difficult or impossible. Instead, if you tie your computers together with a wireless LAN, you can be networked with no reconstruction whatsoever.