I started playing with raylib to make a game that is the opposite of Asteroids. Just to start, I need to be able to draw a triangle that is rotated by some angle around its center, and that’s simple if you understand transformations. Raylib does include a raymath module to do basic vector math, but not specifically what I needed.
So, again, I’m feeling The Unreasonable Effectiveness of Mathematics in Programming. I’m not sure you can make any reasonable game without some transformations.