I would prefer something that functions both on and off line. A home assistant dashboard will be useless while you, for example, reboot the server. You would want something that stores all it needs locally and gets pushes from a server. Though I don't know what that would be ..
As the importance of a system increases your attention to stability must also increase.
Edit: you probably want something that is locked down as well so that the user doesn't accidently click to a different screen or exit the app.