It’s pressing a button three times to enable, three times to disable (with a passcode).

I would say that’s better because it doesn’t take up more phone real-estate, and it can’t be disabled by a smart kiddo.

No, it's not like that at all. You have to not just enable it but also select inaccessible areas of the screen. Every time. And they get greyed out which makes it unusable for watching videos while disabling inadvertent interactions (accidental pause/resume/rewind etc).

You don’t have to disable any part of the screen. Just hit “start” and you are locked into the app. I just tested it and the only thing I could not do was change the volume.

You've missed my point completely. I want the _whole damn screen_ disabled so I don't inadvertently press pause/skip forward when watching videos for example. It's exactly the opposite of the behavior you get from "guided access" thing.

I apologize, I misread what you said. In options (bottom left of the screen) there is a switch to disable touch completely (it also seems to remember it’s setting for that particular app).

There's an option to disable all touches without greying anything out, but I agree that it's too cumbersome to use.