Sorry to double post but I’ve thought of another good thing about this.
With restricted areas, this brings up crime. So as your city grows it can attract crime such as thieves. Thieves will steal from stockpiles and granaries and whatnot. This means we have a real reason to set up guards on patrol. If a guard spots anyone in a restricted area that shouldn’t be there, they can be taken to dungeons or something. Patrolling guards look badass (especially with torches) and it will give us a real reason to think about the layout of the city and guard posts and all.