The proof she presents in Part 2 (t=15:00) on software changes propagating through a system is perhaps the best theoretical justification I have ever seen for Object Oriented design principles and encapsulation:
It's a strong case for loose coupling, but that can be achieved with object oriented programming, functional programming, or any number of other paradigms.
https://youtu.be/AW7ZHpKuqZg?si=Dzt6JeoX7MDT8D9M&t=899