Magic has been a part of WB.SE from the beginning. The problem with magic is that it absolutely fails the standard SE test for being "opinion based," which is defined as:
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.
The problem, of course, is that no one has expert experience, facts, references, or specific expertise in magic.
For this reason we've had to redefine POB. Here, it's not from the answerer's point of view, but from the OP's point of view. If a question is asked such that there's no obvious or sensible way the OP can determine a best answer (other than by their own opinion, AKA, flipping a coin), then it's POB.
Thus, magic survives on the site.
Remember that this site is about helping people develop clear and consistent rules for a fictional world. Magic's just another applied rule — and that's how we draw the line. Is the OP defining the rules for his/her world? Then the question is on-topic. Is the OP simply trying to figure out how to tell their story? Off-topic.
I summarized all this in a POB description here, including a lot of links to the very Meta posts that you want to read.