Ceremonial magick provides structure when dealing with ambiguity. The routine and actions reinforce your psychological beliefs, theoretically strengthening your magick. Humans love ritual as it helps integrate the psychological as well. For those who are not in touch with their Will, the ceremony helps build it.
Perhaps not the best analogy - Ceremonial magick is like stationary machines at a gym. They're complicated, specific, and need to be done in a very certain way, but they ensure results and are very effective. Do you need to use a cross cable lat isolating machine? Of course not. You could lift free weights instead, but that isn't that easy either. If you've never walked into a gym, you can read the instructions on a machine and then try it yourself. You won't be perfect, but you'll be close enough - even on your first try. Now, if you've never walked into a gym before, and there's a giant intimidating row of free weights with no instructions and no clear idea what to do with them, what do you do? I would start with the machines, lol.