Any information on 3D graphics will use a lot of matrix operations. Matrices may not be the fastest way to do 3D operations but they are the standard. It is also important to understand matrices well. Just being familiar with them isn't enough. In order to make things run fast and to come up with cool new ways to do things you have to understand how things work.
Understanding is important for all aspects of computer programming.
Know how and what to optimize. 3D graphics requires a lot of calculations. Even at 3Dfx where we have the incredible Voodoo graphics chipsets to optimize our accelerate our rendering we still have to work hard to optimize transformations inorder to acheive optimal frame rates.