My theory is that Magicians or Sages or whatever name you give to those who control magic trough long studies and use long incantations, can produce more powerful and destructive spells, but that same power maked them take more time and preparation, that's why this chasters usually have some sort of armored protectors, or chant from a secure place.
Menwhile Wizards and wiches, or similar practicioners use less powerful magic, but it can be used with shorter incantations, or even no incantation, just concentrating magic on a device, obviously, they can use magic more ofthen but less effective.
it's like the difference betwen a pistol and a shotgun, yes shotguns do a lot of damage to many targets, but they have a lot of recoil and are hard to use in close combat, plus have fewer shots, menwhile a pistol or handgun, has shorten range and targets, but is fast, easy to use and great on close combat, MCs will be like an assault rifle, many fast shots on close enviroments.