The controller also hooks into their switches, security gateways, etc to give you a single interface to control all the Ubiquiti gear on your network. If you ju

The controller also hooks into their switches, security gateways, etc to give you a single interface to control all the Ubiquiti gear on your network. If you just have their access points, the only reasons you might want to run it after getting the APs configured are checking the status of things and logging (for example, I can work out the schedule for a local wifi-enabled bus service by seeing when their access points were visible to my access points.) Once your APs are configured, you can shut the controller down and they will hum along just fine. I imagine the phone app you used accomplishes much the same thing.