Reasons put this in your library:
Harry Potter-esque. Mistery and magic school.
The cast is more mature so you don't have to deal with certain issues. There is one person that is juat an annkying brat.
Characters feel like humans. Especially because od the dialog. They are given a good backstory which make sense with their personality.
Planar warfare allows for expansive future content.
Underlying plotlines with potential tragedy. (personally one of the reasons i can hardly quit since i do hope for a conclusion that either helps the protagonist grow or a happy ending)
Chosen one, but not really. There is help and work required and 'plot armor' comes with drawbacks/consequences.
I would put most work on the site at a 3.5 on average. So this 5 is meant as a comparison.