The application for this would not be security centric.
This would be more for light applications. In an earlier topic a person was looking for. Something like this for table top RPG. So for example the dungeon Master might need to access a player’s character sheet. The character sheet would be visible to the Player and game masters.
The umbrella component that the one fellow made looks good. However it seems broken when I tried it out. But of course I believe even that one could be fairly easy to compromise. If not mistaken like disabling Java. Or even a clever person who knows about site safe-mode. Can safe mode be restricted to Staff/Admin?
Any component as it is client side mods are if course not meant for security needs. Even a tampermonkey script can be used by members similar or same as theme/theme components
Extend this idea further and you could In theory obscure content based on Badges etc…