Or you can learn about them in school and be given neither a real-world use case nor a rationale or derivation for mmul.
Or you can encounter them in college, and there the experience depends on whether it’s a good or bad kind of a linalg class. But even there – after all the painstaking definitions and lemmas and derivations – it’s easy to end up not grokking how mmul does what it does even if you grasp all the building blocks – vector spaces, bases, how matrices can represent bases and systems of linear equations and linear operations on vectors and how they’re all kinda equivalent.
