The idea is simple. Why not make smartphones with dual WiFi capabilities. The idea is that you should in case of emergency be able to share any type of Internet connection your phone has with others. So with this. Your phone can share an already established WiFi connection. Simply by using the second WiFi chip as a hotspot.
In other situations. For instance with guests you can easily share the home WiFi connection from your phone. The password would then be the temporary hotspot password instead of the home WiFi password.
With two WiFi cards on the phone. Such sharing should be much easier to achieve.