Compare to, say, "A Wizard of Earthsea", where magic is explained in a different way that points out that while a wizard could transmute one substance into another, no wizard would, because of the far-reaching ramifications.
The system was not fully elucidated by any means, but the subtlety of it was suggested by such things as Ged deducing that the doorkeeper was one of the seven masters of Roke.
Well, magic still needs to follow some kind of rules for it to be usable. Otherwise "magic" would just be something random (or maybe chaotic - we just haven't figured out the rules well enough).
In this rare instance, the comic is SFW, but still be wary. https://www.oglaf.com/claret/