Watch that portion of the video again…You have to understand that their are many variations that come into play and all simply can’t be covered. In your case you would typically have a detached structure that is being fed by a branch circuit. Trust me, you want this versus having us comment on what you would do if you installed a panel…because we would then say you need a grounding electrode system?
What you have done is build an extreme into the equation…one thing about electrical training is that as we all see it goes on and on and on as so many versions of installations come into play and dfferent codes have to be dealt with.
In your case, I will have to say that if you intended to install a panel for additional loads you would be also having an issue with 225.39(D) and the 60A minimum requirement for your disconnection means ratings. So lets call them switches and you intended to meet the other requirements I posted earlier and slap your wrist and dont do it again…lol
label the panel as 120V Loads Only.