The really great thing about anatomy is that it goes hand in hand with realism. A life drawing course will teach you more than just a basic understanding of how the body LOOKS; it also gives you a deeper understanding of what's under the skin and how those parts work in tandem with one another. A basic understanding of anatomy allows any style to look fluid and natural, no matter how realistic or "cartoony" that style may appear to be.

Most art schools do want you to be able to work in realism as well as illustration, however; it's that understanding of how the world really looks that gives your art that very natural feel. So in the end, my recommendation is yes, most definitely take it seriously! It will be a great help in the long run. C: Hope this helps!