Artin very wisely identifies these matrix groups as more fundamental–and they are. They come up much more in mathematics. Linear algebra is the central subject of mathematics. You cannot learn too much linear algebra. That’s the basic principle for all of you going on in mathematics.
Linear algebra is presented as sort of stupid stuff, [but] you cannot learn too much linear algebra.
in Abstract Algebra, Lecture 2 at 14:25 via Harvard Extension