If you use various WIFI networks, sometimes you want to locate a list of in networks to automatically join. The key reason is security; you not connect to a WIFI that you don’t trust, mainly if you would like to visit sites that have your confidential information (bank details, credit card info, etc).

The reason is performance; you are not connecting slow network if you have a faster network in range. Some times you forget to connect to the right network so make a list of suitable network is a good idea.