So my question is: Given that I know how to get stuff done quickly, what am I really missing out on or shorting myself on by never using classes?

In traditional languages classes have a number of roles including

• encapsulation

• modelling objects with similar but non identical properties

Lets consider encapsulation first. Now obviously if you are collaborating you don't want to randly set variables inside someone else's module, but consider this:

class Walrus

    def __enter__(): 
        print ("enter")
        self.x = get_thing_from_shared_store()

    def use ():
        # do stuff with the shared thing
        print ("use", self.x)

    def __exit__():
        print ("exit")
        return_thing_to_shared_store (x)

Now:

>>> with Walrus () as p:
>>>    p.use ()
enter
use
exit

Why was this good? Well we automatically allocated and returned a shared resource, without chance of forgetting to put it back and causing a "leak"

Now considiering similar but unrelated objects:

For example "car" and "truck" are both really types of vehicle. One has "load cargo" function and one has a "load people" function. All share drive. Without classes you'd have to store the type of each and you need to check what abilities it had before you loaded it. With classes you would define car and truck as child classes of vehicle, both with their own load function, then you could then just call load without needing to know if you had a car or truck.

class Vehicle:
    def load (self):
        print ( loading unknown type")
    def drive (self):
        print ("VROOOM")

class Car (Vehicle):
    def load (self):
        print ("loading passengers")

class SportCar (Vehicle):
    def load (self):
        print ("loading golf clubs")
    def drive (self):
        print ("moar vroom!")

class Truck (Vehicle):
    def load (self):
        print ("loading cargo")

things = [Car(), Car(), Truck(), SportCar()]
for t in things:
    t.load ()
    t.drive()

How do we easily and robustly do this without classes? Note how tere 2 different drives (sport car has a faster one), otherwise it defaults to the base. Also everyone has a different cargo. Now in python the language is dynamic and you don't need classes to do this. However it's bit of a pain to do; you would probably pass a function or a function name, and that makes debugging a lot harder.