It 100% needs to be in when changing configuration and if you want the logging and tracking features of UniFi then you need to have it running all the time. A used Cloud Key Gen 1 is about £20 these days so why wouldn’t you have one?
These days you can set up the access points from the phone app. It’s significantly less learning curve than it used to be. I live this stuff every day and every day I still find out something new. It’s a vast subject and the development is currently going pretty quickly.For someone using UniFi kit I would assume they knew what they were doing.
Gary - we do not all need to be experts, just know where/who to ask, in my case my son and the OP here….