The really important concepts for ML are least squares, eigenvalues and vectors, and SVD. Those concepts are not very relevant to game programming.
Well, least squares can be solved with projection, which is relevant for converting between coordinate spaces. But game dev isn't going to give you that intuition.
So while the book in question might not be the best resource, it probably is a better starting point than the linked doc.
Thanks for your comment, it made me feel less alone.