Why you should try them
Although books can be a great guide on your artistic journey, nothing can beat having an actual teacher in flesh and bones, who can guide you step by step and answer on the spot further questions you might have. One of the best things of having a teacher is the fact that they will notice your mistakes early on and will help you fix them before these mistakes become a habit.
Another reason you should consider enrolling in an online course is because, in contrast to the tutorial books that can vary in all types of information and can be targeted at people of all levels, the online courses are always targeted towards specific people (whether beginners or experts) and the information presented within them is always in an orderly manner and moving one step at a time. Having a teacher who has studied this art, can put you on the right path and teach you the basic structure before you get into the details; the same way you can't have a human without a skeletal structure, it would be pointless to study how the skin wrinkles and how to draw the mouth before you learn the muscles on which said skin supports itself.
So, if the books can't satisfy your thirst for learning, or if you wish another helping hand to explain things a little better for you, here are some online courses I suggest for bettering the art of making comics.