[rthomas6]

I thought like you for several years. Then one day, I needed a custom type. You can use dicts (or lists, or namedtuples, I guess?), but it just ends up being cleaner and more idiomatic to define a class for the type, because you can define common methods for them.

The article mentions quaternions. If you make a quaternion type (class), you can define addition, multiplication, comparison, etc. for it (methods). If you represent a quaternion any other way, you can't say a * b. Or maybe you can, but I don't know how.

[lvass]

You can represent it as whatever and monkey patch it's __mul__. It's a bit complicated with standard library structures that may be implemented in C, though.