The creation of magic circles was something that one had to master in order to advance as a user of Magic, no matter what their focus was. At some point, it was just a basic necessity. Of course, it was obviously possible to make use of different elements in their raw state with just your body, but this required a comparatively immense amount of mana as well as incredible control, with minimal return when compared to Magic Circles.
While they required you to be static during their creation, except if you had specifically practiced the creation of Magic Circles while mobile, which was something that took even more control. There were different ways to create Magic Circles as well, out of which two methods were the most widespread.
As you might be able to see, from today on, Demon's Virtue is a premium novel! I hope all of you keep reading :D