I know you're talking about drawing animu girls, and the answer is yes, you absolutely need realism. All decent Japanese artists first learned the anatomy, perspective and other fundimentals and then applied their unique style over those. That's what makes anime look more interesting than most Western cartoons, where most artists are art school rejects that were unable to handle realism and went the easy route of IT'S NOT SHITTY ART IT'S MY STYLE.
Grind the fundamentals, only then you will be able to draw true animu girls. Don't be like modern Calarts """"""animators"""""" and have some respect for yourself.