Linear Algebra it's essential for any type of game you want to make.
What if I want to make a Match 3 game using Game Maker or Construct 2? What if I want to make a text adventure? Or interactive fiction using Inform? How about an old-school Rogue-like?
Linear algebra is certainly very useful and a good thing to learn, but saying it is essential for any type of game is overstating it. There are also a great many people who find learning that sort of material from a book to be overly difficult and off-putting but may have significantly less issues staying motivate if they instead learn as they go by picking up topics once they actually have a use for them in a real project. ...and yes, really making games often involves doing a lot of boring and difficult things, but there's no real reason someone should be forced to learn a difficult topic up front before getting started with anything else.