The Ubiquiti controller is not needed for general operation, unless you're using a guest hotspot. Otherwise if it's offline you just lose ability to do configuration and it's data/stats logging.

It's also needed if you want to have any control over SSID's such as enabling/disabling on a schedule, bandwidth limiting and so on.

Hah, that's a dream world where enabling/disabling SSID's ever worked properly.

They have a good UI, good hardware but the software seems half baked.

Originally with the switch to the "new settings", the schedules were switched between the AP's and the UDM, not sure about a dedicated cloud controller.

Great product, poor QA I think.

Laziness? I can just set it up with a couple of clicks and pay almost nothing (it runs on a t2).