You can use it to tap into both open, and secure networks. Sharing the wifi connection from your cellphone using the router as a repeater has some advantages. Case example: Suppose you are at field day or something and a group of you are doing computer logging, QRZ lookups etc. at the same time. Routing the wifi from the cellphone, through the router will result in a more powerful signal for better coverage, and since it's a network device by design, it can handle multiple IP connections and network traffic better than the cell phone on it's own does. Another example involves the idea of tethering one cellphones data plan connection through the Wifi router, and sharing it with multiple other cellphones, tablets etc. with no data plan connection capabilities. That can actually save money because if you have the Wifi repeater, you can share the data connection through the wifi router to all the other phones without requiring each phone / device etc. to subscribe to it's own data plan. There's other similar scenarios where a wifi repeater comes in handy especially when using it from an RV, or outdoor location situation. ..