Nobody wants to see everybody blast each other to Kingdom come with a wand or whatever, so there has to be an agreement over what powers can be used where. Likewise some powers are banned when it would give unfair advantages to one particular magical group. Else they will dominate, rebellion will inevitably occur if those unfair advantages are used against others, and magical war benefits nobody. Put enough magic through land and it will become barren. It would be easy for a magical war to break out and for the end result to be there is nothing left to live in or rule over!
So how does your magical government work out what powers to allow, which to ban and how do they ensure those with the banned powers don't actually use them? There has to be someone more powerful than the rest to ensure fair play (which is where my Fairy Queen, Roxannadrell, comes in as far as my stories are concerned). That person has to be seen to act justly otherwise they will not win the trust of their people (without which they would find it hard to govern). So how does the system work on your fictional world? Who is in overall control and who are they answerable to? The Queen is answerable to her Council, whether she likes it or not.