Does OOP serve a purpose?

Aside from encapsulating data well and making generalisation fanbois wet?

>>9
Abstract data types are not restricted to OOP methodologies. So no on that. I'm not sure what you mean by hierarchical data types, nevertheless I'd probably consider the following to be OOP: -

Objects
Inheritance
Dynamic dispatch
Encapsulation
Subtype polymorphism

OOP is poorly defined.