You can run the controller locally or from the cloud. When it is running locally you have the option to tunnel to it through the cloud. It runs completely locally.
AFAICT, the controller is needed for fast roaming of clients.
AFAICT, the controller is needed for fast roaming of clients.
So can I just ignore that option or do they make me register to the stinking cloud just in case?
IIRC the controller is needed to configure your AP anyway when you first set it up.
Indeed. You need the controller running first before you can configure AP, Switches, and gateways.