I haven't read at all, but just from my experience in fantasy games and novels, when they are differentiated like that, it usually means that they have different sources of power, and ways to get stronger.
Like in D&D there are magic users whose magic is based off their wisdom stat, some based on int stat, and even some based on charisma. In story format maybe one uses spirit/Holy power, one uses ambient mana, while one cultivates mana? Idk hope that helps
